CVE-2026-67236

RabbitMQ is a messaging and streaming broker. From 4.2.0 until 4.2.8 and 4.3.2, a successful POST /login caused is_authorized/2 to set an auth cookie containing base64-encoded username:password credentials without HttpOnly, Secure, SameSite, or expiration protections. Because base64 is encoding rather than encryption, an attacker with same-origin cross-site scripting, an HTTP-readable network position, or local access to the browser cookie store could recover the actual login credentials; older browsers that treated an absent SameSite attribute as None also sent the cookie cross-site. This issue is fixed in versions 4.2.8 and 4.3.2.

• https://github.com/rabbitmq/rabbitmq-server/commit/df9e7f4c0afd311a672705f020d301efad355745Patch
• https://github.com/rabbitmq/rabbitmq-server/commit/edf1fbc7217aaf736955d2e13c9534901a2e0778Patch
• https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.8Release Notes
• https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.2Release Notes
• https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-88vh-gx85-p36mExploit