A flaw was found in Jenkins. A remote attacker could exploit a vulnerability in the origin validation of requests made through the Command Line Interface (CLI) WebSocket endpoint. By manipulating the Host or X-Forwarded-Host HTTP headers, an attacker can perform Domain Name System (DNS) rebinding attacks. This allows bypassing the origin validation, potentially leading to unauthorized actions within the Jenkins environment.

Jenkins 2.442 through 2.554 (both inclusive), LTS 2.426.3 through LTS 2.541.2 (both inclusive) performs origin validation of requests made through the CLI WebSocket endpoint by computing the expected origin for comparison using the Host or X-Forwarded-Host HTTP request headers, making it vulnerable to DNS rebinding attacks that allow bypassing origin validation.

Jenkins has a DNS rebinding vulnerability in WebSocket CLI origin validation