CVE-2026-25531
📋 TL;DR
This vulnerability allows authenticated Kanboard users to duplicate tasks into projects they shouldn't have access to, bypassing permission controls. It affects Kanboard installations before version 1.2.50 where users have authenticated access. This is an incomplete fix for a previous authorization vulnerability.
💻 Affected Systems
- Kanboard
📦 What is this software?
Kanboard by Kanboard
⚠️ Risk & Real-World Impact
Worst Case
Malicious authenticated users could duplicate sensitive tasks into unauthorized projects, potentially exposing confidential project information or disrupting project workflows.
Likely Case
Users accidentally or intentionally duplicating tasks into projects they shouldn't access, causing data leakage and project management confusion.
If Mitigated
With proper project access controls and monitoring, impact is limited to minor data integrity issues within authorized project boundaries.
🎯 Exploit Status
Exploitation requires authenticated access and knowledge of project/task IDs. The vulnerability is straightforward to exploit once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.2.50
Vendor Advisory: https://github.com/kanboard/kanboard/security/advisories/GHSA-vrm3-3337-whp9
Restart Required: Yes
Instructions:
1. Backup your Kanboard database and files. 2. Download Kanboard 1.2.50 or later from the official repository. 3. Replace existing installation files with new version. 4. Restart your web server. 5. Verify functionality.
🔧 Temporary Workarounds
Disable task duplication feature
allRemove or restrict access to the duplicateProjects endpoint via web server configuration or application modifications.
# Example for Apache: RewriteRule ^/index.php\?controller=TaskCreationController&action=duplicateProjects - [F]
# Example for Nginx: location ~* duplicateProjects { return 403; }
Implement additional permission checks
allAdd custom middleware or modify application code to validate user permissions for target projects before allowing task duplication.
# Requires modifying Kanboard source code to add permission validation in TaskCreationController
🧯 If You Can't Patch
- Implement strict project access controls and monitor for unusual task duplication activity
- Restrict user permissions to minimize potential impact and audit all user access levels
🔍 How to Verify
Check if Vulnerable:
Check Kanboard version in admin panel or by examining the application files. Versions below 1.2.50 are vulnerable.Check Version:
Check Kanboard version in Settings > About or examine app/constants.php for version informationVerify Fix Applied:
After upgrading to 1.2.50+, test that authenticated users cannot duplicate tasks into projects they lack access to.📡 Detection & Monitoring
Log Indicators:
- Multiple task duplication events from same user
- Task duplication attempts to projects user shouldn't access
- Unusual task creation patterns in audit logs
Network Indicators:
- POST requests to duplicateProjects endpoint with different project IDs
- Unusual API call patterns to task creation endpoints
SIEM Query:
source="kanboard" AND (action="duplicate" OR endpoint="duplicateProjects") | stats count by user, target_project