# CVE-2026-67419: RabbitMQ topic exchange denial of service via duplicate matchers

Source: https://junglewise.ai/threats/cve-2026-67419-rabbitmq-is-a-messaging-and-streaming-broker-prior-to-4-3-5-an  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-25. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-67419 · Severity: info · Published 2026-09-25

RabbitMQ is a message broker that routes messages between applications. An authenticated user can craft a malicious binding key with multiple wildcard segments to cause the message router to consume excessive CPU and memory, disrupting message delivery for all users on the system.

Technologies: [RabbitMQ](https://junglewise.ai/threats/technologies/rabbitmq-rabbitmq). Vendors: [RabbitMQ](https://junglewise.ai/threats/vendors/rabbitmq).

## Quick answers

**Is CVE-2026-67419 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-67419 being exploited in the wild.

**How severe is CVE-2026-67419?** Informational severity, published 25 September 2026.

**Which products and versions are affected?** RabbitMQ before 4.3.5.

**Is there a fix for CVE-2026-67419?** A patch was published on 2026-08-17: RabbitMQ 4.3.5 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-67419 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-67419?** Check whether you run RabbitMQ at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An authenticated user with permission to bind queues to topic exchanges can use consecutive # (multi-segment) wildcards in binding keys to force the router's trie-node matcher to revisit states without memoization, creating combinatorial computational work. The matcher materializes duplicate destinations before deduplication, leading to memory pressure and routing disruption. The fix limits multi-segment wildcard matchers to two per binding key.

## Affected products

- RabbitMQ RabbitMQ before 4.3.5

## Timeline

- 2026-09-25: disclosed
- 2026-08-17: patched: RabbitMQ 4.3.5 released

## References

- [https://github.com/rabbitmq/rabbitmq-server/commit/c5ed7c4e97e02be688730803604cc7a88dbe4864](https://github.com/rabbitmq/rabbitmq-server/commit/c5ed7c4e97e02be688730803604cc7a88dbe4864)
- [https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.5](https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.5)

## Related threats

- [RabbitMQ OAuth privilege escalation via stale token tags](https://junglewise.ai/threats/cve-2026-67420-rabbitmq-is-a-messaging-and-streaming-broker-from-3-13-0-until-3)
- [RabbitMQ Shovel denial of service via atom exhaustion](https://junglewise.ai/threats/cve-2026-67415-rabbitmq-is-a-messaging-and-streaming-broker-from-4-2-0-until-4-2)
- [RabbitMQ MQTT loopback user bypass via PROXY Protocol](https://junglewise.ai/threats/cve-2026-67411-rabbitmq-is-a-messaging-and-streaming-broker-from-3-13-0-until-3)
- [RabbitMQ OAuth2 client secret exposure via unauthenticated endpoint](https://junglewise.ai/threats/cve-2026-67410-rabbitmq-is-a-messaging-and-streaming-broker-from-4-2-0-until-4-3)
- [RabbitMQ JWKS fetch ignores HTTP response status code](https://junglewise.ai/threats/cve-2026-67409-rabbitmq-is-a-messaging-and-streaming-broker-from-3-13-0-until-4)