Medium severity · published Sep 23, 2026
CVE-2026-66080
RabbitMQ: Super-stream partitions unbounded allocation
4.9
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 24% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RA
rabbitmq-server · rabbitmq
>= 4.1.0, < 4.1.11; >= 4.2.0, < 4.2.6 · source: vendor
RS
Rabbitmq Server · Broadcom
4.1.0 before 4.1.11; 4.2.0 before 4.2.6 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-66080
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-66080
Release Notes
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6
Release Notes
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.0
Vendor Advisory
https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-wg79-5449-m728
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