Jenkins GitLab Plugin is vulnerable to cross-site scripting, caused by improper validation of user-supplied input by the multiple user-provided values. A remote authenticated attacker could exploit this vulnerability to inject malicious script into a Web page which would be executed in a victim’s Web browser within the security context of the hosting Web site, once the page is viewed. An attacker could use this vulnerability to steal the victim’s cookie-based authentication credentials.
Jenkins GitLab Plugin 1.5.34
Refer to Jenkins Security Advisory for patch, upgrade or suggested workaround information.