CVE-2026-67404: RabbitMQ: OAuth2 silent verify_none fallback for JWKS fetch

Severity: high (CVSS 7.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-23 · updated 2026-10-19
Weakness: CWE-295

Description

RabbitMQ is a messaging and streaming broker. Prior to versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0, When no CA bundle is available, ssl_options/1 falls back to [{verify, verify_none}] with no warning. An attacker in a man-in-the-middle position can forge the JWKS response, which leads the broker to accept arbitrary JWTs. Preconditions include The OAuth2 plugin must be in use with no cacertfile configured and the OS CA bundle empty or unreadable (for example, in a minimal container), and the attacker must hold a network man-in-the-middle position.. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0.

Affected products

rabbitmq-server: from 3.13.0 before 3.13.15; from 4.0.0 before 4.0.20; from 4.1.0 before 4.1.11; from 4.2.0 before 4.2.6 — fixed in 3.13.15, 4.0.20, 4.1.11, 4.2.6

How to fix

Upgrade to a fixed version: rabbitmq-server 3.13.15, 4.0.20, 4.1.11, 4.2.6. Check the vendor advisory for mitigations.

References

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