CVE-2026-67404 rabbitmq CVE debrief

Who should care

Defenders responsible for RabbitMQ deployments, particularly those using the OAuth2 plugin, should assess their exposure and prioritize upgrading to a fixed version. This includes verifying the OAuth2 plugin configuration and ensuring proper OS CA bundle setup to prevent potential man-in-the-middle attacks and arbitrary JWT acceptance. Security teams and vulnerability management teams should also review the configuration and impact on their environments.

Why it matters

CVE-2026-67404 is a critical vulnerability in RabbitMQ that allows an attacker to forge JWKS responses and lead the broker to accept arbitrary JWTs when no CA bundle is available. Defenders should prioritize upgrading to a fixed version, verifying the OAuth2 plugin configuration, and ensuring proper OS CA bundle setup to prevent potential man-in-the-middle attacks and arbitrary JWT acceptance.

• Potential for arbitrary JWT acceptance due to lack of CA bundle verification
• Possible man-in-the-middle attacks on RabbitMQ instances
• Need for verification of OAuth2 plugin configuration and OS CA bundle setup
• Priority for upgrading to fixed RabbitMQ versions to prevent exploitation

Technical summary

The vulnerability occurs when no CA bundle is available, causing the ssl_options/1 function to fall back to [{verify, verify_none}] with no warning. This allows an attacker in a man-in-the-middle position to forge the JWKS response and lead the broker to accept arbitrary JWTs. The issue arises in RabbitMQ versions prior to 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0. Affected deployments using the OAuth2 plugin should prioritize upgrading to a fixed version, verifying plugin configuration, and ensuring proper OS CA bundle setup.

Defensive priority

Defenders should prioritize upgrading to a fixed version of RabbitMQ, verifying the configuration of the OAuth2 plugin, and ensuring the OS CA bundle is properly configured.

Recommended defensive actions

• Upgrade to a fixed version of RabbitMQ (3.13.15, 4.0.20, 4.1.11, 4.2.6, or 4.3.0)
• Verify the configuration of the OAuth2 plugin
• Ensure the OS CA bundle is properly configured
• 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 CVE record and NVD vulnerability detail page provide information on the vulnerability, its impact, and the fixed versions. The RabbitMQ server releases and security advisories provide additional context on the issue and the fixes.

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.