Vulnerability · Published Sep 23, 2026 · Assigned by GitHub_M

CVE-2026-67405RabbitMQ: CSWSH on Web-STOMP / Web-MQTT (no Origin validation)

Medium 5.3

In plain English

A medium-severity security flaw in rabbitmq-server from rabbitmq. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.3Medium

Exploit odds (30 days)0.1%top 98.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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, Neither the Web-MQTT handler (deps/rabbitmq_web_mqtt/src/rabbit_web_mqtt_handler.erl:104) nor the Web-STOMP handler (deps/rabbitmq_web_stomp/src/rabbit_web_stomp_handler.erl:102) validates the Origin header on the WebSocket upgrade. Under ssl_cert_login=true, the browser presents the client certificate automatically, so an attacker's JavaScript running in the victim's browser can authenticate as the victim. Preconditions include The non-default configuration use_http_auth=true (Web-STOMP) or ssl_cert_login=true (both plugins) must be enabled. The issue is harmless under the default in-band CONNECT credential configuration.. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, 4.2.6, and 4.3.0.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	rabbitmq-server	no fix listed	DEBIAN-CVE-2026-67405
Debian:13	rabbitmq-server	no fix listed	DEBIAN-CVE-2026-67405
Debian:14	rabbitmq-server	4.3.0-2	DEBIAN-CVE-2026-67405
Ubuntu:22.04:LTS	rabbitmq-server	no fix listed	UBUNTU-CVE-2026-67405
Ubuntu:24.04:LTS	rabbitmq-server	no fix listed	UBUNTU-CVE-2026-67405
Ubuntu:26.04:LTS	rabbitmq-server	no fix listed	UBUNTU-CVE-2026-67405

Affected products (as reported)

Vendor	Product	Versions
rabbitmq	rabbitmq-server	>= 3.13.0, < 3.13.15>= 4.0.0, < 4.0.20>= 4.1.0, < 4.1.11>= 4.2.0, < 4.2.6

Weakness: CWE-1385 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

References

https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-9c4f-rxxm-88q3 x_refsource_CONFIRM
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6 x_refsource_MISC
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.0 x_refsource_MISC