CVE-2021-21660 : What You Need to Know

Jenkins Markdown Formatter Plugin 0.1.0 and earlier versions are affected by a stored cross-site scripting (XSS) vulnerability, allowing attackers to exploit crafted link target URLs.

Understanding CVE-2021-21660

This CVE affects the Jenkins Markdown Formatter Plugin and poses a security risk due to unsanitized link target URLs.

What is CVE-2021-21660?

CVE-2021-21660 refers to a stored cross-site scripting vulnerability in Jenkins Markdown Formatter Plugin versions 0.1.0 and earlier, enabling attackers to execute XSS attacks.

The Impact of CVE-2021-21660

This vulnerability allows attackers with access to edit descriptions using the configured markup formatter to execute malicious scripts, compromising the integrity of the affected systems.

Technical Details of CVE-2021-21660

The technical details of CVE-2021-21660 include:

Vulnerability Description

Jenkins Markdown Formatter Plugin 0.1.0 and earlier do not properly sanitize crafted link target URLs, leading to a stored cross-site scripting vulnerability.

Affected Systems and Versions

The vulnerability affects Jenkins Markdown Formatter Plugin versions less than or equal to 0.1.0.

Exploitation Mechanism

Attackers can exploit this vulnerability by manipulating link target URLs to inject and execute malicious scripts.

Mitigation and Prevention

To address CVE-2021-21660, consider the following:

Immediate Steps to Take

Upgrade Jenkins Markdown Formatter Plugin to a version beyond 0.1.0 that contains a patch for this vulnerability.
Regularly monitor for any suspicious activities on Jenkins instances.

Long-Term Security Practices

Implement regular security audits and vulnerability assessments on Jenkins plugins.
Educate users about safe coding practices to prevent XSS vulnerabilities.

Patching and Updates

Apply security patches and updates promptly to ensure the protection of Jenkins environments against known vulnerabilities.