CVE-2026-44838

NameCVE-2026-44838
DescriptionRabbitMQ is a messaging and streaming broker. From 4.2.0 to before 4.2.4, RabbitMQ's MQTT plugin allows for topic-level authorization using regular expressions with variable substitution. Administrators can create patterns such as ^{client_id}-sensors$ to restrict user access to topics that include their client ID. However, the client_id is provided by the user in the MQTT CONNECT packet and is inserted into the regex pattern without escaping special regex characters. This flaw enables an authenticated MQTT user to inject regex operators to bypass authorization. This vulnerability is fixed in 4.2.4 and 4.3.0.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
rabbitmq-server (PTS)bullseye (security), bullseye3.8.9-3+deb11u1fixed
bookworm, bookworm (security)3.10.8-1.1+deb12u1fixed
trixie4.0.5-6+deb13u2fixed
forky4.0.5-14fixed
sid4.3.0-2fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
rabbitmq-serversource(unstable)(not affected)

Notes

- rabbitmq-server <not-affected> (Vulnerable code never in Debian released version)
https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-x866-xp2g-cx8v

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