Bug 2539764 (CVE-2026-67240) - CVE-2026-67240 RabbitMQ: RabbitMQ: Denial of Service via crafted AMQP 1.0 SQL LIKE filter
Summary: CVE-2026-67240 RabbitMQ: RabbitMQ: Denial of Service via crafted AMQP 1.0 SQL...
Keywords:
Status: NEW
Alias: CVE-2026-67240
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
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Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-23 20:34 UTC by OSIDB Bzimport
Modified: 2026-09-24 06:32 UTC (History)
0 users

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Description OSIDB Bzimport 2026-09-23 20:34:22 UTC
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.


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