Medium 5.9Published Sep 23, 2026

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

Updated under an hour ago (Oct 27, 2026, 2:30 AM ET)

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It affects rabbitmq-server and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 5.9 MEDIUM (v4.0, CNA)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
Weakness (CWE): CWE-770
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Sep 24, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

rabbitmq rabbitmq-server rabbitmq:server (from the name)	from 4.1.0, < 4.1.11; from 4.2.0, < 4.2.6	CNA record
broadcom rabbitmq_server broadcom:rabbitmq_server	from 4.1.0 before 4.1.11; from 4.2.0 before 4.2.6	NVD

References

References

https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-wg79-5449-m728	x-refsource-confirm, vendor-advisory
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6	x-refsource-misc, release-notes
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.0	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.