RabbitMQ: CORS * reflects Origin with Allow-Credentials

Summary

RabbitMQ is a messaging and streaming broker. Prior to versions 3.13.17, 4.0.22, 4.1.13, and 4.2.6, match_origin/1 returned the bare reflected Origin and allowed credentials even when the wildcard "" was configured, so the response echoed the attacker's origin together with Access-Control-Allow-Credentials. The affected code is rabbit_mgmt_cors.erl. When the management plugin is configured with a wildcard CORS origin (cors_allow_origins = ""), the handler reflects the request Origin back in Access-Control-Allow-Origin and also sends Access-Control-Allow-Credentials: true. A malicious web page that a signed-in administrator visits can then use that administrator's cached HTTP Basic credentials to issue authenticated, state-changing requests to the management API. Preconditions include The management plugin is configured with the wildcard cors_allow_origins = "*", which is an explicit operator misconfiguration A target administrator has a cached HTTP Basic-auth session in the browser. This issue is fixed in versions 3.13.17, 4.0.22, 4.1.13, and 4.2.6.

Timeline

1. Sep 23, 2026, 7:59 PM UTCCVE published
2. Sep 24, 2026, 2:16 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Sep 24, 2026, 2:17 PM UTCRecord last updated

Affected versions

• rabbitmq rabbitmq-server

  From 3.13.0 · fixed in 3.13.17; From 4.0.0 · fixed in 4.0.22; From 4.1.0 · fixed in 4.1.13; From 4.2.0 · fixed in 4.2.6

• rabbitmqBitnami

  From 3.13.0 · fixed in 3.13.17; From 4.0.0 · fixed in 4.0.22; From 4.1.0 · fixed in 4.1.13; From 4.2.0 · fixed in 4.2.6

References 2