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.

  • Published Sep 25, 2026
  • CVSS 8.2 high
  • 0.1% chance of exploitation in the next 30 days (EPSS)
  • A fix is available

Affected software

CVE-2026-67236 at the National Vulnerability Database