Attack Chain

Given the nature of the advisory, a generic attack chain is described below. Specific steps depend on the exploited vulnerability in each plugin.

1. An attacker identifies a vulnerable Jenkins plugin version.
2. The attacker crafts a malicious request targeting a specific endpoint of the vulnerable plugin.
3. The request exploits a vulnerability, such as arbitrary code execution, bypass authentication, or cross-site scripting (XSS).
4. The Jenkins server processes the malicious request, leading to unauthorized code execution.
5. The attacker gains access to sensitive information, such as credentials stored within Jenkins.
6. The attacker uses the compromised credentials to access other systems or escalate privileges within the Jenkins environment.
7. The attacker modifies build configurations to inject malicious code into software builds.
8. The attacker compromises software builds and injects malicious code, impacting downstream users of the software.

Impact

Successful exploitation of these vulnerabilities could lead to unauthorized access to sensitive information, arbitrary code execution on the Jenkins server, and compromise of software builds. This can result in supply chain attacks, data breaches, and reputational damage. The scope of impact depends on the specific vulnerabilities exploited and the access level obtained by the attacker. The Jenkins Security Advisory addresses vulnerabilities in multiple plugins, any of which if exploited, could have significant impacts.

Recommendation

• Review the Jenkins Security Advisory 2026-04-29 and identify vulnerable plugins in your environment.
• Update the Credentials Binding Plugin to a version greater than 719.v80e905ef14eb_.
• Update the GitHub Plugin to a version greater than 1.46.0.
• Update the GitHub Branch Source Plugin to a version greater than 1967.vdea_d580c1a_b_a_.
• Update the HTML Publisher Plugin to a version greater than 427.
• Update the Matrix Authorization Strategy Plugin to a version greater than 3.2.9.
• Update the Microsoft Entra ID (previously Azure AD) Plugin to a version greater than 666.v6060de32f87d.
• Update the Script Security Plugin to a version greater than 1399.ve6a_66547f6e1.
• Monitor Jenkins webserver logs (category webserver, product linux) for suspicious activity and unauthorized access attempts after applying the updates.