CVE-2026-67419 rabbitmq CVE debrief

Who should care

RabbitMQ administrators and users who can bind queues to topic exchanges and publish to them should assess exposure and prioritize verification and patching. This includes reviewing RabbitMQ versions, applying patches, and monitoring for suspicious activity to prevent potential denial-of-service attacks.

Why it matters

Defenders should prioritize verifying RabbitMQ versions and assessing exposure, as this vulnerability can cause significant disruptions to routing. RabbitMQ administrators and users who can bind queues to topic exchanges and publish to them should verify their versions and apply patches to prevent potential denial-of-service attacks.

• Disruption to routing for all tenants
• Combinatorial CPU work and memory pressure
• Potential denial-of-service attack

Technical summary

The vulnerability is caused by the lack of memoization in RabbitMQ's topic matchers, allowing an authenticated user to disrupt routing for all tenants. This weakness can be exploited by using consecutive # segments in a binding key, leading to combinatorial CPU work and memory pressure. The vulnerability has been addressed in RabbitMQ version 4.3.5, which should be applied to prevent potential denial-of-service attacks. RabbitMQ administrators and users who can bind queues to topic exchanges and publish to them should assess exposure and prioritize verification and patching.

Defensive priority

Defenders should prioritize verifying RabbitMQ versions and assessing exposure, as this vulnerability can cause significant disruptions to routing.

Recommended defensive actions

• Verify RabbitMQ version and assess exposure
• Apply patch to upgrade to RabbitMQ version 4.3.5
• Monitor for suspicious activity and potential disruptions to routing
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability is fixed in RabbitMQ version 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. This issue has been verified through source references and official advisories.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.