CVE-2025-47889: Jenkins WSO2 Oauth Auth Bypass Flaw

CVE-2025-47889 Overview

CVE-2025-47889 is a critical authentication bypass vulnerability in the Jenkins WSO2 OAuth Plugin version 1.0 and earlier. The vulnerability stems from improper validation of authentication claims by the "WSO2 Oauth" security realm, allowing unauthenticated attackers to log in to Jenkins controllers using any username and any password combination, including usernames that do not exist in the system.

Critical Impact

Unauthenticated attackers can gain complete access to Jenkins controllers by bypassing authentication entirely, potentially leading to unauthorized code execution, data theft, and supply chain compromise.

Affected Products

• Jenkins WSO2 OAuth Plugin version 1.0 and earlier
• Jenkins controllers configured to use the WSO2 OAuth security realm

Discovery Timeline

• May 14, 2025 - CVE-2025-47889 published to NVD
• June 12, 2025 - Last updated in NVD database

Technical Details for CVE-2025-47889

Vulnerability Analysis

This vulnerability is classified as CWE-287 (Improper Authentication), representing a fundamental failure in the plugin's authentication mechanism. The WSO2 OAuth Plugin fails to properly validate authentication claims received during the OAuth authentication flow. When a user attempts to authenticate through the WSO2 OAuth security realm, the plugin accepts any authentication claim without verifying its authenticity or validity against the OAuth provider.

This architectural flaw means that an attacker can craft arbitrary authentication responses that the plugin will accept as valid, completely bypassing the intended authentication controls. The vulnerability is particularly severe because it affects the security realm itself—the core component responsible for protecting access to the Jenkins controller.

Root Cause

The root cause of CVE-2025-47889 lies in the complete absence of validation logic for OAuth authentication claims within the WSO2 OAuth Plugin. The plugin trusts authentication responses without cryptographic verification, signature validation, or token introspection. This design oversight allows any incoming authentication claim to be processed as legitimate, regardless of its origin or content.

Attack Vector

The attack vector for this vulnerability is network-based and requires no prior authentication or user interaction. An attacker can exploit this vulnerability remotely by:

1. Navigating to a Jenkins controller configured with the WSO2 OAuth security realm
2. Submitting a login request with any arbitrary username and password combination
3. The vulnerable plugin accepts the authentication claim without validation
4. The attacker gains authenticated access to the Jenkins controller with the privileges of the specified username

The vulnerability allows attackers to impersonate any user, including administrators, by simply specifying their username during the authentication attempt. Even non-existent usernames are accepted, potentially creating sessions for users that were never intended to have access.

Due to the nature of this authentication bypass vulnerability, exploitation does not require specialized code. Attackers can simply submit standard HTTP login requests to the Jenkins authentication endpoint. For detailed technical information about this vulnerability, refer to the Jenkins Security Advisory #SECURITY-3481.

Detection Methods for CVE-2025-47889

Indicators of Compromise

• Unexpected or anomalous login events in Jenkins audit logs, particularly for users with elevated privileges
• Authentication events from unusual IP addresses or geographic locations
• Login attempts for usernames that do not exist in your identity provider
• Sudden appearance of new user sessions without corresponding valid OAuth provider authentication records

Detection Strategies

• Enable and monitor Jenkins audit logging for all authentication events
• Cross-reference Jenkins authentication logs with WSO2 Identity Server logs to identify discrepancies
• Implement network monitoring to detect authentication attempts that bypass the expected OAuth flow
• Deploy intrusion detection rules to alert on direct authentication submissions to Jenkins endpoints

Monitoring Recommendations

• Configure real-time alerting for any authentication events involving administrative accounts
• Establish baseline authentication patterns and alert on deviations
• Monitor for bulk login attempts or credential stuffing patterns targeting the Jenkins authentication endpoint
• Review Jenkins access control configurations and user permission changes regularly

How to Mitigate CVE-2025-47889

Immediate Actions Required

• Immediately disable the WSO2 OAuth Plugin if it is installed and in use
• Switch to an alternative authentication method such as Jenkins' built-in user database, LDAP, or a different OAuth plugin
• Audit all recent Jenkins authentications to identify potential unauthorized access
• Review and revoke any suspicious user sessions currently active on the Jenkins controller

Patch Information

As of the latest information available, administrators should consult the Jenkins Security Advisory #SECURITY-3481 for official patch information and remediation guidance. Until a patched version is available, the plugin should be disabled entirely.

Workarounds

• Disable the WSO2 OAuth Plugin and configure an alternative security realm
• Implement network-level access controls to restrict Jenkins access to trusted networks only
• Enable Jenkins security hardening features including CSRF protection and agent-to-controller security
• Consider placing Jenkins behind a reverse proxy with additional authentication requirements

# Disable the WSO2 OAuth Plugin via Jenkins CLI
java -jar jenkins-cli.jar -s http://your-jenkins-url/ disable-plugin wso2-oauth-plugin

# Alternatively, remove the plugin directory manually (requires Jenkins restart)
# Navigate to $JENKINS_HOME/plugins/ and remove:
rm -rf $JENKINS_HOME/plugins/wso2-oauth-plugin*

# Restart Jenkins to apply changes
systemctl restart jenkins