RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.3.3 and 4.2.9 and 4.1.14 and 4.0.23, Incomplete fix for CVE-2026-44838: escaperegexchar/1 does not escape -, leaving room for an MQTT topic permission bypass. the CVE-2026-44838 fix made expandtopicpermission/2 escape regex metacharacters in expanded topic-permission variables (escaperegex(V)), but escaperegexchar/1 escapes \ ^ $ . | ? + ( ) [ ] { } and omits -. When a topic permission template places {clientid} inside a [...] character class A low-privileged authenticated MQTT user controlling its clientid can broaden topic authorization (read and write) when templates embed {clientid} in a [...] This issue is fixed in versions 4.3.3 and 4.2.9 and 4.1.14 and 4.0.23.
Fix
Patch, vendor advisory and mitigation references on NVD 1
- https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-q46v-hrvq-hp24 Vendor Advisory, Exploit, Mitigation
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 5.1 · broadcomNVD modified 2026-10-16 16:10
Affected (CPE criteria) 1
cpe:2.3:a:broadcom:rabbitmq_server:*:*:*:*:*:*:*:*
References 3
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.9 Release Notes
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.3 Release Notes
- https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-q46v-hrvq-hp24 Vendor Advisory, Exploit, Mitigation