# CVE-2026-66080: rabbitmq-server: RabbitMQ is a messaging and streaming broker

CVE-2026-66080 is fixed in rabbitmq-server on 1 platform by DEBIAN-CVE-2026-66080 (version 4.3.0-2), released September 25, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-66080
- Priority: Routine
- CVSS: 4.9 (medium)
- EPSS: 0.0032
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 23, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | rabbitmq-server Debian 14 | 4.3.0-2 | [DEBIAN-CVE-2026-66080](https://patchblox.com/security/data/fix/linux/debian-cve-2026-66080.md) | Sep 25, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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