Vulnerability · Published Sep 23, 2026 · Assigned by GitHub_M

CVE-2026-66080RabbitMQ: Super-stream partitions unbounded allocation

Medium 5.9

In plain English

A medium-severity resource allocation without limits in rabbitmq-server from rabbitmq. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 25% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.9Medium

Exploit odds (30 days)0.3%top 75.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

RabbitMQ is a messaging and streaming broker. Prior to versions 4.1.11, 4.2.6, and 4.3.0, validate_partitions only checks that the requested partition count is at least 1, with no upper bound. A large count such as lists:seq(0, 500000000) allocates roughly 8GB. Preconditions include The rabbitmq_stream_management plugin must be enabled. The caller needs the management tag and access to the target vhost.. This issue is fixed in versions 4.1.11, 4.2.6, and 4.3.0.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:13	rabbitmq-server	no fix listed	DEBIAN-CVE-2026-66080
Debian:14	rabbitmq-server	4.3.0-2	DEBIAN-CVE-2026-66080
Ubuntu:22.04:LTS	rabbitmq-server	no fix listed	UBUNTU-CVE-2026-66080
Ubuntu:24.04:LTS	rabbitmq-server	no fix listed	UBUNTU-CVE-2026-66080
Ubuntu:26.04:LTS	rabbitmq-server	no fix listed	UBUNTU-CVE-2026-66080

Affected products (as reported)

Vendor	Product	Versions
rabbitmq	rabbitmq-server	>= 4.1.0, < 4.1.11>= 4.2.0, < 4.2.6

Weakness: CWE-770 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References

https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-wg79-5449-m728 x_refsource_CONFIRM
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6 x_refsource_MISC
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.0 x_refsource_MISC