{"affected":[{"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-6g32-pxv4-2wfj/GHSA-6g32-pxv4-2wfj.json"},"package":{"ecosystem":"Maven","name":"com.rabbitmq:amqp-client","purl":"pkg:maven/com.rabbitmq/amqp-client"},"ranges":[{"events":[{"introduced":"0"},{"fixed":"5.33.0"}],"type":"ECOSYSTEM"}],"versions":["1.3.0","1.5.4","1.5.5","1.6.0","1.7.2","1.8.0","1.8.1","2.0.0","2.1.0","2.1.1","2.2.0","2.3.0","2.3.1","2.4.1","2.5.0","2.5.1","2.6.0","2.6.1","2.7.0","2.7.1","2.8.0","2.8.1","2.8.2","2.8.3","2.8.4","2.8.5","2.8.6","2.8.7","3.0.0","3.0.1","3.0.2","3.0.3","3.0.4","3.1.0","3.1.1","3.1.2","3.1.3","3.1.4","3.2.0","3.2.1","3.2.2","3.2.3","3.2.4","3.3.0","3.3.1","3.3.2","3.3.3","3.3.4","3.3.5","3.4.0","3.4.1","3.4.2","3.4.3","3.4.4","3.5.0","3.5.1","3.5.2","3.5.3","3.5.4","3.5.5","3.5.6","3.5.7","3.6.0","3.6.1","3.6.2","3.6.3","3.6.4","3.6.5","3.6.6","4.0.0","4.0.1","4.0.2","4.0.3","4.1.0","4.1.1","4.10.0","4.11.0","4.11.1","4.11.2","4.11.3","4.12.0","4.2.0","4.2.1","4.2.2","4.3.0","4.4.0","4.4.1","4.4.2","4.5.0","4.6.0","4.7.0","4.8.0","4.8.1","4.8.2","4.8.3","4.9.0","4.9.1","4.9.2","4.9.3","5.0.0","5.1.0","5.1.1","5.1.2","5.10.0","5.11.0","5.12.0","5.13.0","5.13.1","5.14.0","5.14.1","5.14.2","5.14.3","5.15.0","5.16.0","5.16.1","5.17.0","5.17.1","5.18.0","5.19.0","5.2.0","5.20.0","5.21.0","5.22.0","5.23.0","5.24.0","5.25.0","5.26.0","5.27.0","5.27.1","5.28.0","5.29.0","5.3.0","5.30.0","5.31.0","5.32.0","5.4.0","5.4.1","5.4.2","5.4.3","5.5.0","5.5.1","5.5.2","5.5.3","5.6.0","5.7.0","5.7.1","5.7.2","5.7.3","5.8.0","5.9.0"]}],"aliases":["CVE-2026-63337"],"database_specific":{"cwe_ids":["CWE-470"],"github_reviewed":true,"github_reviewed_at":"2026-08-18T16:32:29Z","nvd_published_at":null,"severity":"HIGH"},"details":"The JSON-RPC tools in `com.rabbitmq.tools.jsonrpc` perform `Class.forName(javaReturnType)` with `initialize=true` on class names received from untrusted AMQP messages, without any validation or allowlist.\n\n**Vulnerable code** (`ProcedureDescription.java:101-127`):\nWhen a `JsonRpcClient` connects, it calls `system.describe` and receives a service description from the AMQP queue. The response JSON includes `javaReturnType` fields that are reflectively set via `JSONUtil.tryFill()`, triggering `setJavaReturnType()` → `computeReturnTypeAsJavaClass()` → `Class.forName(javaReturnType)`.\n\n**Attack scenario:**\n1. Victim uses `JsonRpcClient` to connect to a JSON-RPC service via RabbitMQ\n2. Attacker (co-tenant on shared broker, or MITM) intercepts the `system.describe` request\n3. Attacker responds with crafted `javaReturnType` values\n4. Victim's client calls `Class.forName(attackerInput)` with default `initialize=true`\n5. Static initializers of attacker-specified classes execute in victim's JVM\n\nAdditionally, the loaded class from `getReturnType()` is passed to `mapper.parse(replyStr, expectedType)` at `JsonRpcClient.java:168`, potentially enabling type-confusion.\n\n**Recommended fix:** Use `Class.forName(javaReturnType, false, classLoader)` to prevent static initializer execution, or add an allowlist of permitted return types.\n\n**CWE:** CWE-470\n\n---\n\n**Reply from reporter (2026-06-29):** Thanks for the quick turnaround. Fix looks good. Looking forward to the CVE assignment.","id":"GHSA-6g32-pxv4-2wfj","modified":"2026-09-10T03:51:13.214436792Z","published":"2026-08-18T16:32:29Z","references":[{"type":"WEB","url":"https://github.com/rabbitmq/rabbitmq-java-client/security/advisories/GHSA-6g32-pxv4-2wfj"},{"type":"WEB","url":"https://github.com/rabbitmq/rabbitmq-java-client/pull/2000"},{"type":"WEB","url":"https://github.com/rabbitmq/rabbitmq-java-client/pull/2002"},{"type":"WEB","url":"https://github.com/rabbitmq/rabbitmq-java-client/commit/0032f75f9dc3df847f94b2b85a16119250bf63cb"},{"type":"WEB","url":"https://github.com/rabbitmq/rabbitmq-java-client/commit/9f8e7efd0c648f235dc0e96232ae7efa75ea4fa8"},{"type":"PACKAGE","url":"https://github.com/rabbitmq/rabbitmq-java-client"},{"type":"WEB","url":"https://github.com/rabbitmq/rabbitmq-java-client/releases/tag/v5.33.0"}],"schema_version":"1.9.0","severity":[{"score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L","type":"CVSS_V4"}],"summary":"RabbitMQ Java client: Unvalidated Class.forName in JSON-RPC ProcedureDescription enables arbitrary class loading"}