CVE-2021-21635 : What You Need to Know

Jenkins REST List Parameter Plugin version 1.3.0 and earlier is vulnerable to stored cross-site scripting (XSS) attacks due to improper input neutralization.

Understanding CVE-2021-21635

This CVE involves a security vulnerability in the Jenkins REST List Parameter Plugin that allows attackers with Job/Configure permission to exploit stored XSS.

What is CVE-2021-21635?

The CVE-2021-21635 is a stored cross-site scripting (XSS) vulnerability in Jenkins REST List Parameter Plugin versions 1.3.0 and earlier. Attackers with Job/Configure permission can exploit this flaw.

The Impact of CVE-2021-21635

This vulnerability could allow malicious actors to execute arbitrary scripts in the context of a user's browser, leading to sensitive data theft, unauthorized actions, or further attacks.

Technical Details of CVE-2021-21635

The technical details include a description of the vulnerability, affected systems and versions, and the exploitation mechanism.

Vulnerability Description

The vulnerability arises from the lack of proper escaping of a parameter name reference in embedded JavaScript code.

Affected Systems and Versions

Jenkins REST List Parameter Plugin version 1.3.0 and earlier are affected by this vulnerability.

Exploitation Mechanism

Attackers with Job/Configure permission can exploit this vulnerability by injecting malicious scripts via the parameter name reference.

Mitigation and Prevention

To address CVE-2021-21635, immediate steps should be taken followed by long-term security practices and patching.

Immediate Steps to Take

Users should update the Jenkins REST List Parameter Plugin to a non-vulnerable version and monitor for any unusual activities.

Long-Term Security Practices

Implement secure coding practices, conduct regular security audits, and educate users about XSS risks.

Patching and Updates

Stay informed about security advisories from Jenkins and promptly apply patches to ensure protection against known vulnerabilities.