CVE-2025-29926: XWiki Platform Auth Bypass Vulnerability

CVE-2025-29926 Overview

CVE-2025-29926 is an authorization bypass vulnerability in the XWiki Platform's WikiManager REST API that allows any user to create a new wiki instance with administrative privileges. This flaw stems from missing authorization checks in the REST API endpoints, enabling attackers to escalate their privileges and perform unauthorized operations across the entire XWiki farm environment.

Critical Impact

Any authenticated user can exploit this vulnerability to become a wiki administrator, potentially compromising the entire XWiki farm installation through subsequent attacks.

Affected Products

• XWiki Platform versions prior to 15.10.15
• XWiki Platform versions 16.0.0 through 16.4.5
• XWiki Platform versions 16.5.0 through 16.9.x

Discovery Timeline

• 2025-03-19 - CVE-2025-29926 published to NVD
• 2025-05-13 - Last updated in NVD database

Technical Details for CVE-2025-29926

Vulnerability Analysis

This vulnerability affects the WikiManager REST API component, which is an optional extension for XWiki Platform that must be manually installed through the extension manager. The core issue lies in missing authorization controls (CWE-862) and improper authorization implementation (CWE-285) within the REST API endpoints responsible for wiki creation and management.

When exploited, an attacker with any level of authentication can invoke the WikiManager REST API to create a new wiki instance. During this creation process, the attacker is automatically granted administrative privileges on the newly created wiki. This administrative access can then be leveraged as a foothold for further attacks against the XWiki farm, including accessing sensitive data across wikis, modifying configurations, or exploiting other vulnerabilities that require elevated privileges.

The attack is particularly concerning because it transforms a low-privileged user into an administrator without proper authorization checks, violating the principle of least privilege.

Root Cause

The root cause of CVE-2025-29926 is the absence of proper authorization checks in the WikiManager REST API. The API endpoints responsible for wiki creation do not verify whether the requesting user has the necessary permissions to perform such operations. This missing access control allows any authenticated user to exercise functionality that should be restricted to administrators only.

Attack Vector

The vulnerability is exploitable over the network without user interaction. An attacker needs only basic authentication to the XWiki platform to exploit this flaw. The attack flow involves:

1. Authenticating to the XWiki platform with any valid user credentials
2. Sending a crafted REST API request to the WikiManager endpoint to create a new wiki
3. Obtaining administrative privileges on the newly created wiki instance
4. Using the elevated privileges to conduct further attacks on the XWiki farm

The vulnerability mechanism involves REST API endpoints that accept wiki creation requests without validating the caller's authorization level. When a request is received, the API processes it and grants the requesting user administrative rights on the new wiki, regardless of their original permission level. For technical implementation details, refer to the GitHub Security Advisory.

Detection Methods for CVE-2025-29926

Indicators of Compromise

• Unexpected creation of new wiki instances by non-administrator users
• Audit logs showing REST API calls to WikiManager endpoints from unauthorized accounts
• Users gaining administrative privileges without proper authorization workflows
• Unusual activity patterns in wiki creation logs originating from low-privileged accounts

Detection Strategies

• Monitor REST API access logs for calls to WikiManager endpoints by non-administrator users
• Implement alerting for wiki creation events triggered by users without admin privileges
• Review user permission changes and escalations across the XWiki farm environment
• Deploy application-layer firewalls to detect and block unauthorized WikiManager API requests

Monitoring Recommendations

• Enable verbose logging for the WikiManager REST API component
• Configure alerts for any wiki creation events that deviate from normal administrative workflows
• Regularly audit the list of wikis and their associated administrators for unauthorized entries
• Monitor for suspicious patterns of privilege escalation across the XWiki deployment

How to Mitigate CVE-2025-29926

Immediate Actions Required

• Upgrade XWiki Platform to version 15.10.15, 16.4.6, or 16.10.0 or later immediately
• If immediate upgrade is not possible, consider temporarily disabling or removing the WikiManager REST API extension
• Audit existing wikis for unauthorized instances created by non-administrator users
• Review and revoke any suspicious administrative privileges granted through this vulnerability

Patch Information

The vulnerability has been patched in XWiki Platform versions 15.10.15, 16.4.6, and 16.10.0. The fix implements proper authorization checks in the WikiManager REST API to ensure only users with appropriate permissions can create new wikis. The patch commit is available at the GitHub Commit Changes page. Additional details are tracked in XWiki Jira Issue XWIKI-22490.

Workarounds

• Temporarily disable or uninstall the WikiManager REST API extension if not required for operations
• Implement network-level access controls to restrict access to the WikiManager REST API endpoints
• Configure reverse proxy rules to block unauthorized requests to WikiManager API paths
• Enforce strict authentication requirements and limit user account creation until patching is complete

# Example: Disable WikiManager REST API through XWiki Extension Manager
# Navigate to: Administration > Extensions > Installed Extensions
# Find "WikiManager REST API" and click "Uninstall"

# Alternative: Block WikiManager API at reverse proxy level (nginx example)
location ~ ^/xwiki/rest/wikis {
    # Only allow access from trusted admin IP addresses
    allow 10.0.0.0/8;
    deny all;
}