Publish GHSA-3f24-pcvm-5jqc

Author: advisory-database[bot]

advisories/github-reviewed/2026/03/GHSA-3f24-pcvm-5jqc/GHSA-3f24-pcvm-5jqc.json

@@ -0,0 +1,81 @@
+{
+  "schema_version": "1.4.0",
+  "id": "GHSA-3f24-pcvm-5jqc",
+  "modified": "2026-03-24T21:51:08Z",
+  "published": "2026-03-24T21:51:08Z",
+  "aliases": [
+    "CVE-2026-33248"
+  ],
+  "summary": "NATS has mTLS verify_and_map authentication bypass via incorrect Subject DN matching",
+  "details": "### Background\n\nNATS.io is a high performance open source pub-sub distributed communication technology, built for the cloud, on-premise, IoT, and edge computing.\n\nOne authentication model supported is mTLS, deriving the NATS client identity from properties of the TLS Client Certificate.\n\n### Problem Description\n\nWhen using mTLS for client identity, with `verify_and_map` to derive a NATS identity from the client certificate's Subject DN, certain patterns of RDN would not be correctly enforced, allowing for authentication bypass.\n\nThis does require a valid certificate from a CA already trusted for client certificates, and `DN` naming patterns which the NATS maintainers consider highly unlikely.\n\nSo this is an unlikely attack. Nonetheless, administrators who have been very sophisticated in their `DN` construction patterns might conceivably be impacted.\n\n### Affected Versions\n\nFixed in nats-server 2.12.6 & 2.11.15\n\n### Workarounds\n\nDevelopers should review their CA issuing practices.",
+  "severity": [
+    {
+      "type": "CVSS_V3",
+      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N"
+    }
+  ],
+  "affected": [
+    {
+      "package": {
+        "ecosystem": "Go",
+        "name": "github.com/nats-io/nats-server/v2"
+      },
+      "ranges": [
+        {
+          "type": "ECOSYSTEM",
+          "events": [
+            {
+              "introduced": "0"
+            },
+            {
+              "fixed": "2.11.15"
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "package": {
+        "ecosystem": "Go",
+        "name": "github.com/nats-io/nats-server/v2"
+      },
+      "ranges": [
+        {
+          "type": "ECOSYSTEM",
+          "events": [
+            {
+              "introduced": "2.12.0-RC.1"
+            },
+            {
+              "fixed": "2.12.6"
+            }
+          ]
+        }
+      ]
+    }
+  ],
+  "references": [
+    {
+      "type": "WEB",
+      "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-3f24-pcvm-5jqc"
+    },
+    {
+      "type": "WEB",
+      "url": "https://advisories.nats.io/CVE/secnote-2026-13.txt"
+    },
+    {
+      "type": "PACKAGE",
+      "url": "https://github.com/nats-io/nats-server"
+    }
+  ],
+  "database_specific": {
+    "cwe_ids": [
+      "CWE-287",
+      "CWE-295"
+    ],
+    "severity": "MODERATE",
+    "github_reviewed": true,
+    "github_reviewed_at": "2026-03-24T21:51:08Z",
+    "nvd_published_at": null
+  }
+}