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CVE-2026-67407GHSA-q46v-hrvq-hp24

rabbitmq-server: RabbitMQ: Incomplete fix for CVE-2026-44838: `escape_regex_char/1` does not escape `-`, leaving room for an MQTT topic permission bypass

rabbitmq rabbitmq-server
Open in ThreatlineRecord JSON
CVSS
5.1Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.23%Chance of exploitation activity in the next 30 days, higher than 12% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in4.3.3Also 4.2.9, 4.1.14 and 1 moreGitHub
Published25 Sep 2026Updated 25 Sep 2026CVE List

What fixes it

  • 4.3.3rabbitmq-server, rabbitmqGitHub
  • 4.2.9rabbitmq-server, rabbitmqGitHub
  • 4.1.14rabbitmq-server, rabbitmqGitHub
  • 4.0.23rabbitmq-server, rabbitmqGitHub

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

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.

Text from CVE List

Affected versions 8

  • rabbitmq-serveraffected: >= 4.3.2, < 4.3.3CVE List
  • rabbitmq-serveraffected: >= 4.2.0, < 4.2.9CVE List
  • rabbitmq-serveraffected: >= 4.1.0, < 4.1.14CVE List
  • rabbitmq-serveraffected: >= 4.0.0, < 4.0.23CVE List
  • rabbitmq-server, rabbitmq>= 4.3.2, < 4.3.3GitHub
  • rabbitmq-server, rabbitmq>= 4.2.0, < 4.2.9GitHub
  • rabbitmq-server, rabbitmq>= 4.1.0, < 4.1.14GitHub
  • rabbitmq-server, rabbitmq>= 4.0.0, < 4.0.23GitHub

References 3