CVE-2026-67242: RabbitMQ: OAuth2 is_integer(Exp) guard skips token-expiry checks for float exp

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-25 · updated 2026-10-16
Weakness: CWE-613

Description

RabbitMQ is a messaging and streaming broker. From 4.2.0 until 4.2.9 and 4.3.3, OAuth2 isinteger(Exp) guard skips token-expiry checks for float exp. validatetokenexpiry/1 (lines 208-214) and expirytimestamp/1 (138-144) both guard with 'when isinteger(Exp)' and fall through to ok/never for float values. josejwt:verify validates only the signature, not exp. With float exp, no expiry validation occurs anywhere in the If the IdP emits exp as a JSON float (RFC 7519 permits fractional NumericDate), both the login-time expiry check and the mid-connection disconnect timer are silently skipped , an already-expired token is accepted, and connections never time OAuth2 backend enabled IdP emits float exp (uncommon; mainstream IdPs emit integers) Attacker possesses a previously-valid signed. This issue is fixed in versions 4.2.9 and 4.3.3.

Affected products

rabbitmq-server: from 4.2.0 before 4.2.9; from 4.3.0 before 4.3.3 — fixed in 4.2.9, 4.3.3

How to fix

Upgrade to a fixed version: rabbitmq-server 4.2.9, 4.3.3. Check the vendor advisory for mitigations.

References

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