CVE-2026-67240 RabbitMQ: ReDoS via AMQP 1.0 SQL filter LIKE wildcard
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-67240?
CVE-2026-67240 is a low-severity vulnerability in rabbitmq-server, published on 23 Sep 2026.
Official description
RabbitMQ is a messaging and streaming broker. Prior to versions 4.2.7 and 4.3.1, pattern_to_regex maps % -> .*? and _ -> ., then compiles ^...$ with only [unicode]; re:run is called with only [{capture, none}] - no explicit match_limit. A pattern like %_%_..._%X becomes ^.*?..*?.....*?.X$ with overlapping lazy quantifiers. The whole-expression cap is ?MAX_EXPRESSION_LENGTH=4096 chars / ?MAX_TOKENS=200; a LIKE string literal is one token, so ~2000 %_ pairs fit. SQL filters are accepted unconditionally at rabbit_amqp_session.erl:3264 (no feature flag). Evaluated per-message at rabbit_stream_queue.erl:1439. OTP's default 10M match_limit caps each match at ~100-200 ms (not seconds), and the re NIF yields to the scheduler. An authenticated AMQP 1.0 consumer with read+write on a stream queue can cause ~100-200 ms of CPU per delivered message via a crafted LIKE filter, multiplied across thousands of messages and parallel sessions - a substantial backtracking-driven CPU amplification. Preconditions include AMQP 1.0 with stream queues in use Attacker can attach a receiver with a filter (read permission) and publish messages with long property values (write permission). This issue is fixed in versions 4.2.7 and 4.3.1.
Weakness: CWE-1333
Which versions are affected by CVE-2026-67240?
1 open source package ship an affected version, including rabbitmq.
| Package | Affected | Fixed in |
|---|---|---|
rabbitmq Bitnami | From 4.2.0 | 4.2.7, 4.3.1 |
How do I fix CVE-2026-67240?
Upgrade rabbitmq to a fixed version for your release line: 4.2.7 or 4.3.1.
Is CVE-2026-67240 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67240 exists.
Sources
Also known as BIT-rabbitmq-2026-67240, DEBIAN-CVE-2026-67240, GHSA-59c5-553c-57m2, UBUNTU-CVE-2026-67240.