CVE-2026-67240
published 2026-09-23CVE-2026-67240: 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…
PriorityP415low2.3CVSS 4.0
AVNACLATPPRLUINVCNVINVALSCNSINSANEXCRXIRXARXMAVXMACXMATXMPRXMUIXMVCXMVIXMVAXMSCXMSIXMSAXSXAUXRXVXREXUX
EPSS
0.26%
16.7th percentile
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.
Affected
2 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| rabbitmq | rabbitmq-server | — | — |
| rabbitmq | rabbitmq-server | — | — |
CVSS provenance
nvdv4.02.3LOWCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vendor_redhat2.3LOW
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VulDB
RabbitMQ up to 4.2.6/4.3.0 Like Filter rabbit_amqp_session.erl incorrect regex
vuldb·2026-09-23·CVSS 2.3
CVE-2026-67240 [LOW] RabbitMQ up to 4.2.6/4.3.0 Like Filter rabbit_amqp_session.erl incorrect regex
A vulnerability labeled as problematic has been found in RabbitMQ up to 4.2.6/4.3.0. Impacted is an unknown function of the file rabbit_amqp_session.erl of the component Like Filter. Executing a manipulation can lead to incorrect regular expression.
This vulnerability is handled as CVE-2026-67240. The attack can be executed remotely. There is not any exploit available.
The affected component should be upgraded.
Red Hat
RabbitMQ: RabbitMQ: Denial of Service via crafted AMQP 1.0 SQL LIKE filter
vendor_redhat·2026-09-23·CVSS 2.3
CVE-2026-67240 [LOW] CWE-1333 RabbitMQ: RabbitMQ: Denial of Service via crafted AMQP 1.0 SQL LIKE filter
RabbitMQ: RabbitMQ: Denial of Service via crafted AMQP 1.0 SQL LIKE filter
A flaw was found in RabbitMQ, a messaging and streaming broker. An authenticated AMQP 1.0 consumer with read and write permissions on a stream queue can exploit a Regular Expression Denial of Service (ReDoS) vulnerability. This occurs when a crafted LIKE filter is processed, leading to excessive CPU consumption due to inefficient regular expression evaluation. This can result in a denial of service, impacting the availability of the RabbitMQ service.
Package: rabbitmq-server4.2 (Red Hat Hardened Images) - Will not fix
Package: rabbitmq-server4.3 (Red Hat Hardened Images) - Affected
No detection rules found.
No public exploits indexed.
2026-09-23
Published