CVE-2026-21880
📋 TL;DR
Kanboard versions 1.2.48 and below contain an LDAP injection vulnerability in the authentication mechanism. Attackers can manipulate LDAP search filters to enumerate all LDAP users, discover sensitive attributes, and perform targeted attacks against specific accounts. This affects all Kanboard instances using LDAP authentication.
💻 Affected Systems
- Kanboard
📦 What is this software?
Kanboard by Kanboard
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain complete LDAP directory enumeration, exposing all user accounts, email addresses, organizational roles, and other sensitive attributes, potentially enabling credential theft or targeted attacks.
Likely Case
Attackers enumerate LDAP users and extract sensitive information like email addresses and organizational roles, facilitating phishing campaigns or credential stuffing attacks.
If Mitigated
With proper network segmentation and LDAP query logging, impact is limited to information disclosure without direct system compromise.
🎯 Exploit Status
Exploitation requires access to the Kanboard login interface but no authentication. LDAP injection techniques are well-documented and easy to implement.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.2.49
Vendor Advisory: https://github.com/kanboard/kanboard/security/advisories/GHSA-v66r-m28r-wmq7
Restart Required: Yes
Instructions:
1. Backup your Kanboard installation and database. 2. Download version 1.2.49 from the official releases. 3. Replace the existing installation files with the new version. 4. Clear the cache directory. 5. Restart your web server.
🔧 Temporary Workarounds
Disable LDAP Authentication
allTemporarily switch to local authentication or another authentication method until patching is complete.
Edit config.php and set 'LDAP_AUTH' to false or configure alternative authentication
Implement Web Application Firewall Rules
allBlock LDAP injection patterns at the WAF level.
Add WAF rules to filter LDAP special characters: (, ), *, \, =, >, <, ~
🧯 If You Can't Patch
- Implement network-level restrictions to limit Kanboard access to trusted IP addresses only
- Enable detailed LDAP query logging and monitor for unusual search patterns
🔍 How to Verify
Check if Vulnerable:
Check if using Kanboard version 1.2.48 or below with LDAP authentication enabled in config.phpCheck Version:
Check Kanboard version in config.php or via web interfaceVerify Fix Applied:
Verify version is 1.2.49 or higher and test LDAP authentication with injection attempts📡 Detection & Monitoring
Log Indicators:
- Unusual LDAP search patterns in web server logs
- Multiple failed login attempts with special characters
- LDAP queries containing injection characters: (, ), *, \
Network Indicators:
- Unusual traffic to LDAP servers from Kanboard instances
- Multiple authentication requests with varying parameters
SIEM Query:
source="web_server" AND (url="*/auth/login" OR url="*/auth/check") AND (query_string="*%28*%29*" OR query_string="*%3D*" OR query_string="*%5C*")