CVE-2026-67419RabbitMQ: Consecutive topic wildcards cause combinatorial routing work

Description

RabbitMQ is a messaging and streaming broker. Prior to 4.3.5, an authenticated user who can bind a queue to a topic exchange and publish to it can use consecutive # segments in a binding key to make both topic matchers revisit the same trie-node and routing-key-suffix states without memoization. The matcher materializes duplicate destinations before deduplication, causing combinatorial CPU work and memory pressure that can disrupt routing for all tenants. This vulnerability is fixed in 4.3.5.

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

References and patches

• https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-h964-v5mf-22cq Vendor AdvisoryExploitMitigation
• https://github.com/rabbitmq/rabbitmq-server/commit/c5ed7c4e97e02be688730803604cc7a88dbe4864 Patch
• https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.5 Release Notes