CVE-2025-31510
📋 TL;DR
This CVE describes a cross-site scripting (XSS) vulnerability in LemonLDAP::NG's portal login page. Attackers can inject malicious scripts via the tab parameter in Choice authentication, potentially compromising user sessions. Organizations using LemonLDAP::NG versions before 2.21.0 are affected.
💻 Affected Systems
- LemonLDAP::NG
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal user credentials, hijack administrator sessions, and gain unauthorized access to protected systems and data.
Likely Case
Attackers steal user session cookies or credentials, leading to unauthorized access to applications protected by LemonLDAP::NG.
If Mitigated
With proper web application firewalls and input validation, the attack would be blocked or have minimal impact.
🎯 Exploit Status
XSS vulnerabilities are commonly exploited and require minimal technical skill.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.21.0
Vendor Advisory: https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/issues/3341
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Upgrade LemonLDAP::NG to version 2.21.0 or later. 3. Restart the LemonLDAP::NG service. 4. Verify the fix by testing the login page.
🔧 Temporary Workarounds
Input Validation Filter
allImplement server-side validation to sanitize the tab parameter
# Add input validation in portal configuration
# Example: Validate tab parameter contains only alphanumeric characters
# Specific implementation depends on deployment
Web Application Firewall
allDeploy WAF rules to block XSS payloads in the tab parameter
# Example ModSecurity rule:
# SecRule ARGS:tab "@detectXSS" "id:1001,phase:2,deny,status:403"
🧯 If You Can't Patch
- Disable Choice authentication method if not required
- Implement Content Security Policy (CSP) headers to restrict script execution
🔍 How to Verify
Check if Vulnerable:
Test the login page with a payload like: /?tab=<script>alert('XSS')</script> and check if script executesCheck Version:
lemonldap-ng-manager --versionVerify Fix Applied:
After patching, repeat the same test - the script should not execute and the parameter should be sanitized📡 Detection & Monitoring
Log Indicators:
- Unusual tab parameter values containing script tags or JavaScript in access logs
- Multiple failed login attempts with suspicious parameters
Network Indicators:
- HTTP requests with script tags in tab parameter
- Unusual traffic patterns to login page
SIEM Query:
source="lemonldap.log" AND (tab="*<script>*" OR tab="*javascript:*")