RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.0.24, 4.1.15, 4.2.10, and 4.3.4, the optimized AMQP 1.0 server_mode parser in deps/amqp10_common/src/amqp10_binary_parser.erl matches the textual prefixes of symbolic data, sequence, and value body descriptors without verifying their encoded symbol lengths. An authenticated AMQP 1.0 publisher with write permission can submit a well-formed unknown descriptor that begins with a registered body descriptor, and RabbitMQ misclassifies and stores the bytes as a standard body section. Strict AMQP 1.0 consumers can terminate while decoding the stored entry. For bodies misclassified as data, AMQP 0-9-1 or other cross-protocol conversion performs full body decoding and can terminate the consumer protocol process, with acknowledgement-required delivery permitting repeated failures. Sequence and value classifications are normally transported as opaque encoded payloads on that conversion path. The broker remains alive, and the issue does not bypass routing or authorization. This issue is fixed in versions 4.0.24, 4.1.15, 4.2.10, and 4.3.4.
https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-p35w-6mx2-q4pc
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.4
https://github.com/rabbitmq/rabbitmq-server/pull/17287
https://github.com/rabbitmq/rabbitmq-server/pull/17017
https://github.com/rabbitmq/rabbitmq-server/commit/d5186e66e056960f58e2d0fbee2fcc66e1ed6fb9
https://github.com/rabbitmq/rabbitmq-server/commit/c9b4b10c2dbf0f1c89f10b482ac8b45f84dc5954
Published: 2026-10-14
Updated: 2026-10-15
Base Score: 5.5
Vector: CVSS2#AV:N/AC:L/Au:S/C:N/I:P/A:P
Severity: Medium
Base Score: 6.5
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity: Medium
Base Score: 5.3
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00541