CVE-2026-66079 rabbitmq CVE debrief

Who should care

RabbitMQ administrators and users, Network administrators, Security teams, and any operators managing RabbitMQ deployments, as well as vulnerability management and security teams assessing exposure and prioritizing patching or mitigation for this high-severity vulnerability.

Why it matters

CVE-2026-66079 is a high-severity vulnerability in RabbitMQ that can be exploited by an unauthenticated network attacker to crash the RabbitMQ node, leading to a denial-of-service (DoS) condition. RabbitMQ administrators and users, network administrators, and security teams should assess exposure and prioritize patching or mitigation.

• Denial-of-service (DoS) condition
• Crash of the Erlang VM leading to service disruption
• Potential for exploitation by unauthenticated network attackers
• Need for urgent patching or mitigation

Technical summary

The vulnerability is caused by a flaw in the amqp10_framing:decode_bin/1 function, which allows an attacker to exploit the heap memory, leading to a crash of the Erlang VM. An unauthenticated network attacker can crash any RabbitMQ node with the AMQP 1.0 listener enabled by sending a single ~19-byte frame. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, and 4.2.6. The pre-auth incoming_max_frame_size caps the frame, not the Count field, so a 19-byte payload with Count = 0xFFFFFFFF is accepted. No max_heap_size is set on the reader process.

Defensive priority

High

Recommended defensive actions

• Update RabbitMQ to version 3.13.15, 4.0.20, 4.1.11, or 4.2.6
• Disable the AMQP 1.0 listener if not required
• Monitor RabbitMQ node for suspicious activity
• 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 caused by a flaw in the RabbitMQ AMQP 1.0 listener. An attacker can send a specially crafted frame to crash the RabbitMQ node, leading to a denial-of-service (DoS) condition. The vulnerability is fixed in versions 3.13.15, 4.0.20, 4.1.11, and 4.2.6.

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.