RabbitMQ: list_to_atom on auth_mechanism URI tokens in amqp_client

RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.15, 4.0.20, 4.1.11, and 4.2.6, mechanisms/1 applied list_to_atom/1 to every colon-delimited token in an attacker-controlled auth_mechanism value, permanently consuming Erlang VM atoms and allowing the node to be crashed with a large request. Exploitation requires the Shovel or Federation plugin to be in use, and setting auth_mechanism requires the policymaker tag. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, and 4.2.6.

Source published

25 Sep 2026 16:00:16 UTC

Source modified

28 Sep 2026 13:46:28 UTC

Observed here

23 Oct 2026 15:48:27 UTC

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CVSS 4.0 · 5.9 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