CVE-2026-67227: Rabbitmq Rabbitmq-Server

Medium severity, CVSS 5.9. EPSS: 0.3% chance of exploitation in the next 30 days.

RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.0.22 and 4.1.14 and 4.2.7 and 4.3.1, Atom exhaustion: toatom on global-parameter :name. resourceexists/2 (and the PUT/DELETE handlers) call rabbitdatacoercion:toatom/1 on the :name URL path segment. toatom/1 uses binarytoatom/2 (unsafe). The endpoint requires policymaker (not management, but below A user with the policymaker tag can crash the node by exhausting the atom table via repeated requests to /api/global-parameters/:name with unique :name Management plugin enabled policymaker tag ~1M HTTP. This issue is fixed in versions 4.0.22 and 4.1.14 and 4.2.7 and 4.3.1.

Affected products

• Rabbitmq Rabbitmq-Server: from 4.0.0, before 4.0.22 (fixed in 4.0.22); from 4.1.0, before 4.1.14 (fixed in 4.1.14); from 4.2.0, before 4.2.7 (fixed in 4.2.7); from 4.3.0, before 4.3.1 (fixed in 4.3.1)

Published 2026-09-25. Last modified 2026-09-28.