CVE-2026-1962: WeKan Auth Bypass Vulnerability

CVE-2026-1962 Overview

A vulnerability has been identified in WeKan, an open-source kanban board application, affecting versions up to 8.20. The vulnerability exists in the Attachment Migration component, specifically within the server/attachmentMigration.js file. This improper access controls vulnerability (CWE-266: Incorrect Privilege Assignment) allows authenticated attackers to potentially access or manipulate attachment data without proper authorization checks.

Critical Impact

Remote authenticated attackers can exploit improper access controls in the Attachment Migration component to potentially gain unauthorized access to attachments, leading to confidentiality, integrity, and availability impacts.

Affected Products

• WeKan versions up to 8.20
• WeKan Attachment Migration component (server/attachmentMigration.js)

Discovery Timeline

• February 5, 2026 - CVE-2026-1962 published to NVD
• February 5, 2026 - Last updated in NVD database

Technical Details for CVE-2026-1962

Vulnerability Analysis

This vulnerability stems from improper access controls (CWE-266: Incorrect Privilege Assignment) within WeKan's attachment migration functionality. The affected code in server/attachmentMigration.js fails to properly validate user permissions before allowing operations on attachments during the migration process.

The vulnerability is exploitable over the network and requires low privileges to execute. An authenticated user can potentially bypass intended access restrictions to interact with attachments that should be protected. This could result in unauthorized viewing, modification, or deletion of attachment data belonging to other users or boards.

Root Cause

The root cause is an incorrect privilege assignment in the attachment migration logic. The server/attachmentMigration.js component does not adequately enforce access control checks, allowing authenticated users with low privileges to perform operations they should not be authorized to execute. This represents a fundamental flaw in how the application verifies user permissions during attachment-related operations.

Attack Vector

The attack can be initiated remotely over the network by any authenticated user. The attacker leverages the weak access controls in the attachment migration functionality to:

1. Authenticate to the WeKan application with valid credentials
2. Interact with the attachment migration endpoints
3. Bypass authorization checks due to improper access control implementation
4. Potentially access, modify, or delete attachments without proper authorization

The vulnerability requires authentication (low privileges) but no user interaction, making it relatively straightforward to exploit for any user with access to a WeKan instance.

Detection Methods for CVE-2026-1962

Indicators of Compromise

• Unusual access patterns to attachment migration endpoints in WeKan server logs
• Unexpected modification or deletion of attachments by users without proper board permissions
• Anomalous API requests to server/attachmentMigration.js related endpoints
• Users accessing attachment data from boards they are not members of

Detection Strategies

• Monitor WeKan application logs for unauthorized attachment access attempts
• Implement audit logging for all attachment-related operations and review for anomalies
• Deploy web application firewall (WAF) rules to detect suspicious patterns in attachment migration requests
• Use SentinelOne Singularity to monitor for unusual file access patterns associated with WeKan processes

Monitoring Recommendations

• Enable detailed logging for the WeKan application, particularly for attachment operations
• Set up alerts for failed authorization attempts in the attachment migration component
• Regularly review access control configurations and user permissions in WeKan
• Monitor network traffic to WeKan servers for unusual request patterns

How to Mitigate CVE-2026-1962

Immediate Actions Required

• Upgrade WeKan to version 8.21 or later immediately
• Review all user permissions and access levels within the WeKan instance
• Audit recent attachment access logs for signs of unauthorized access
• Consider temporarily restricting access to the WeKan instance until patching is complete

Patch Information

The vulnerability has been addressed in WeKan version 8.21. The fix is available in commit 053bf1dfb76ef230db162c64a6ed50ebedf67eee. Organizations should upgrade to version 8.21 or later to remediate this vulnerability.

For detailed patch information, see:

• GitHub Wekan Release v8.21
• GitHub Commit Changes

Workarounds

• Implement network-level access controls to limit who can reach the WeKan instance
• Use a reverse proxy with additional authentication layers to restrict access to the attachment migration functionality
• Review and restrict user accounts to only those that absolutely require access
• Monitor attachment-related activity closely until the patch can be applied

# Example: Restrict access to WeKan using firewall rules
# Allow only trusted IP ranges to access the WeKan server
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP

# Alternative: Use nginx to add additional access controls
# Add to nginx configuration for WeKan
# location /api/attachments {
#     auth_basic "Restricted Access";
#     auth_basic_user_file /etc/nginx/.htpasswd;
#     proxy_pass http://wekan_backend;
# }