CVE-2026-25563: Wekan Auth Bypass Vulnerability

CVE-2026-25563 Overview

CVE-2026-25563 is an Insecure Direct Object Reference (IDOR) vulnerability affecting WeKan, an open-source kanban board application. The vulnerability exists in the checklist creation and related checklist routes, where the implementation fails to verify that the supplied cardId belongs to the supplied boardId. This authorization gap allows authenticated attackers to perform cross-board ID tampering by manipulating identifiers, potentially accessing or modifying checklist data across different boards without proper authorization.

Critical Impact

Authenticated users can bypass board-level access controls and manipulate checklist data on boards they should not have access to, compromising data integrity across the application.

Affected Products

• WeKan versions prior to 8.19
• wekan_project wekan (all versions before the security patch)

Discovery Timeline

• 2026-02-07 - CVE CVE-2026-25563 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2026-25563

Vulnerability Analysis

This Insecure Direct Object Reference vulnerability stems from insufficient authorization checks in WeKan's checklist functionality. The application exposes routes that accept both boardId and cardId parameters but fails to validate the relationship between these objects. An attacker with valid credentials on one board can craft requests that reference cards belonging to different boards, effectively bypassing board-level access controls.

The vulnerability is classified under CWE-639 (Authorization Bypass Through User-Controlled Key), which describes situations where the application uses user-controlled input to directly access objects without verifying that the user is authorized to access the referenced object. In this case, the application trusts the client-supplied boardId and cardId combination without confirming that the card actually belongs to the specified board.

Root Cause

The root cause of this vulnerability is the absence of proper object-level authorization validation in the checklist creation and related routes. When processing requests, the application accepts boardId and cardId parameters but does not verify that the referenced card is actually a member of the referenced board. This allows attackers to substitute identifiers from boards they have access to with identifiers from boards where they should not have permissions.

Attack Vector

The attack vector is network-based and requires low-privilege authentication. An attacker who has legitimate access to at least one WeKan board can exploit this vulnerability by:

1. Identifying the board ID and card ID of their authorized board
2. Discovering or guessing valid card IDs from other boards (often sequential or predictable)
3. Crafting malicious API requests that combine their authorized board ID with unauthorized card IDs
4. Manipulating checklist data on cards across different boards

Since WeKan is typically accessible over a network and the vulnerability requires only basic authenticated access, the attack surface is broad for multi-tenant deployments or organizations with multiple boards containing sensitive project information.

The vulnerability allows manipulation of checklist data but does not directly enable read access to confidential information or complete system compromise, which accounts for the integrity-focused impact rating.

Detection Methods for CVE-2026-25563

Indicators of Compromise

• Unusual API requests to checklist endpoints with mismatched boardId and cardId parameters
• Failed authorization attempts followed by successful requests with modified object identifiers
• Checklist modifications appearing on boards where the authenticated user lacks proper permissions
• Anomalous patterns of cross-board object references in application logs

Detection Strategies

• Monitor API request logs for checklist routes that show inconsistent board and card ID combinations
• Implement application-level logging to track authorization decisions and flag requests where object ownership validation would fail
• Deploy web application firewalls (WAF) with rules to detect parameter manipulation patterns typical of IDOR attacks
• Use SentinelOne Singularity to monitor for suspicious network activity patterns associated with automated IDOR exploitation tools

Monitoring Recommendations

• Enable verbose logging on WeKan checklist API endpoints to capture all request parameters
• Set up alerts for users accessing cards outside their authorized board scope
• Monitor for enumeration patterns where sequential or brute-force card ID guessing may indicate exploitation attempts
• Review audit logs regularly for unexpected checklist modifications

How to Mitigate CVE-2026-25563

Immediate Actions Required

• Upgrade WeKan to version 8.19 or later immediately
• Audit existing checklist data for unauthorized modifications that may have occurred before patching
• Review access logs for signs of exploitation during the vulnerable period
• Temporarily restrict checklist API access if immediate patching is not possible

Patch Information

WeKan has addressed this vulnerability in version 8.19. The security fix is available through the official GitHub commit. Organizations should update to the patched version as soon as possible. Additional details about the vulnerability can be found in the VulnCheck Advisory and on the Wekan official website.

Workarounds

• Implement network-level access controls to limit which users can reach WeKan checklist API endpoints
• Deploy a reverse proxy or API gateway that validates board membership before forwarding requests to checklist routes
• Restrict user registration and board access to reduce the potential attack surface
• Enable additional authentication factors for sensitive board operations until the patch can be applied

# Example: Restrict access to WeKan API using nginx
# Add to your nginx configuration for WeKan
location ~ ^/api/boards/[^/]+/cards/[^/]+/checklists {
    # Only allow access from trusted internal networks until patched
    allow 10.0.0.0/8;
    allow 192.168.0.0/16;
    deny all;
    
    proxy_pass http://wekan-backend;
}