CVE-2025-24398: Jenkins Bitbucket Server Integration CSRF

CVE-2025-24398 Overview

CVE-2025-24398 is a Cross-Site Request Forgery (CSRF) protection bypass vulnerability affecting the Jenkins Bitbucket Server Integration Plugin. The vulnerability exists in versions 2.1.0 through 4.1.3 (inclusive) and allows attackers to craft malicious URLs that can bypass the CSRF protection mechanisms for any target URL within Jenkins. This could enable unauthorized actions to be performed on behalf of authenticated Jenkins users without their knowledge or consent.

Critical Impact

Attackers can bypass CSRF protections to perform unauthorized actions in Jenkins, potentially leading to configuration changes, credential theft, or build pipeline manipulation on behalf of authenticated users.

Affected Products

• Jenkins Bitbucket Server Integration Plugin versions 2.1.0 through 4.1.3

Discovery Timeline

• 2025-01-22 - Jenkins publishes security advisory SECURITY-3434
• 2025-01-22 - CVE-2025-24398 published to NVD
• 2025-06-06 - Last updated in NVD database

Technical Details for CVE-2025-24398

Vulnerability Analysis

This vulnerability is classified as CWE-352 (Cross-Site Request Forgery). The Jenkins Bitbucket Server Integration Plugin contains a flaw in how it implements CSRF protection mechanisms. The plugin fails to properly validate or enforce CSRF tokens for certain request paths, allowing attackers to construct specially crafted URLs that circumvent these security controls.

When a victim with an active Jenkins session clicks on or is redirected to a malicious URL crafted by an attacker, the Jenkins server will process the request as if it were a legitimate action initiated by the authenticated user. This bypass affects the CSRF protection for any target URL within the Jenkins instance, significantly expanding the attack surface.

The vulnerability requires user interaction—specifically, an authenticated Jenkins user must be tricked into accessing the attacker-controlled URL. However, once this occurs, the attacker gains the ability to perform any action the victim user is authorized to perform within Jenkins.

Root Cause

The root cause lies in improper implementation of CSRF token validation within the Bitbucket Server Integration Plugin. The plugin's request handling logic contains a flaw that allows specially formatted URLs to bypass the standard CSRF token verification process that Jenkins employs to protect against cross-site request forgery attacks.

Attack Vector

The attack is network-based and requires user interaction. An attacker must craft a malicious URL and convince an authenticated Jenkins user to access it. This could be accomplished through phishing emails, malicious websites, or embedding the URL in content the victim is likely to view while authenticated to Jenkins.

The vulnerability mechanism involves crafting URLs that exploit the CSRF protection bypass. For detailed technical information on the specific URL patterns that trigger this vulnerability, refer to the Jenkins Security Advisory SECURITY-3434.

Detection Methods for CVE-2025-24398

Indicators of Compromise

• Unusual or unexpected configuration changes in Jenkins without corresponding user activity
• Jenkins audit logs showing actions performed from external referrer URLs
• Unexpected modifications to Bitbucket Server integration settings or credentials
• Build jobs triggered or modified without legitimate user initiation

Detection Strategies

• Monitor Jenkins access logs for requests to sensitive endpoints with unusual referrer headers
• Review audit trails for actions performed shortly after users accessed external links
• Implement web application firewall rules to detect potential CSRF attack patterns
• Enable and regularly review Jenkins security audit logging for anomalous activity

Monitoring Recommendations

• Configure Jenkins to log all administrative and configuration-changing actions with full request context
• Implement alerting for bulk or rapid configuration changes that may indicate automated exploitation
• Monitor for requests to Jenkins from unexpected domains or IP ranges
• Regularly audit Bitbucket Server Integration Plugin configurations for unauthorized changes

How to Mitigate CVE-2025-24398

Immediate Actions Required

• Upgrade the Jenkins Bitbucket Server Integration Plugin to version 4.1.4 or later immediately
• Review Jenkins audit logs for any suspicious activity that may indicate prior exploitation
• Verify all Bitbucket Server integration configurations for unauthorized modifications
• Educate users about the risks of clicking unknown links while authenticated to Jenkins

Patch Information

Jenkins has addressed this vulnerability in the Bitbucket Server Integration Plugin. Organizations should update to version 4.1.4 or later, which contains the fix for this CSRF protection bypass. The security patch ensures proper CSRF token validation for all protected endpoints. Refer to the Jenkins Security Advisory SECURITY-3434 for complete patch details and upgrade instructions.

Workarounds

• Limit access to Jenkins to trusted networks only until patching is complete
• Implement strict Content Security Policy headers to reduce the risk of CSRF attacks
• Require re-authentication for sensitive administrative actions where possible
• Train users to avoid clicking external links while maintaining active Jenkins sessions

# Verify installed plugin version and update via Jenkins CLI
java -jar jenkins-cli.jar -s http://your-jenkins-url/ list-plugins | grep bitbucket-server-integration

# Update the plugin to the patched version
java -jar jenkins-cli.jar -s http://your-jenkins-url/ install-plugin bitbucket-server-integration -restart