High severity · published Sep 23, 2026
CVE-2026-67405
RabbitMQ: CSWSH on Web-STOMP / Web-MQTT (no Origin validation)
8.1
CVSS
0.1%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 1% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RA
rabbitmq-server · rabbitmq
>= 3.13.0, < 3.13.15; >= 4.0.0, < 4.0.20; >= 4.1.0, < 4.1.11; >= 4.2.0, < 4.2.6 · source: vendor
RS
Rabbitmq Server · Broadcom
3.13.0 before 3.13.15; 4.0.0 before 4.0.20; 4.1.0 before 4.1.11; 4.2.0 before 4.2.6 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-67405
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-67405
Release Notes
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6
Release Notes
https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.0
Vendor Advisory
https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-9c4f-rxxm-88q3
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