CVE-2025-27609
📋 TL;DR
CVE-2025-27609 is a cross-site scripting (XSS) vulnerability in Icinga Web 2 that allows attackers to inject arbitrary JavaScript into the web interface. When exploited, this enables attackers to perform actions on behalf of authenticated users. Organizations running Icinga Web 2 versions prior to 2.11.5 or 2.12.13 are affected.
💻 Affected Systems
- Icinga Web 2
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers can hijack authenticated user sessions, steal credentials, manipulate monitoring data, or pivot to internal systems using the victim's privileges.
Likely Case
Attackers inject malicious scripts to steal session cookies or credentials, potentially gaining unauthorized access to the monitoring system.
If Mitigated
With proper content security policies and modern browsers, the attack surface is significantly reduced, though patching is still recommended.
🎯 Exploit Status
Exploitation requires the attacker to craft a malicious request that the victim interacts with, making it a reflected XSS attack.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.11.5 or 2.12.3
Vendor Advisory: https://github.com/Icinga/icingaweb2/security/advisories/GHSA-5cjw-fwjc-8j38
Restart Required: Yes
Instructions:
1. Backup your Icinga Web 2 configuration and database. 2. Download the patched version from the official Icinga releases. 3. Follow the Icinga Web 2 upgrade documentation for your specific version. 4. Restart the web service after upgrade.
🔧 Temporary Workarounds
Enable Content Security Policy
allFor Icinga Web 2 version 2.12.2 specifically, enable the content security policy in application settings to mitigate the vulnerability.
Navigate to Icinga Web 2 admin interface > Application > Security > Enable Content Security Policy
🧯 If You Can't Patch
- Implement strict web application firewall (WAF) rules to block XSS payloads.
- Ensure all users access Icinga Web 2 only through modern browsers with CORS protection enabled.
🔍 How to Verify
Check if Vulnerable:
Check your Icinga Web 2 version via the web interface footer or configuration files.Check Version:
grep 'version' /etc/icingaweb2/config.ini or check web interface footerVerify Fix Applied:
Verify the version shows 2.11.5 or higher, or 2.12.3 or higher after patching.📡 Detection & Monitoring
Log Indicators:
- Unusual JavaScript payloads in web server access logs
- Multiple failed login attempts from unexpected sources
Network Indicators:
- Suspicious HTTP requests containing script tags or JavaScript code to Icinga Web endpoints
SIEM Query:
source="web_access_logs" AND (url="*<script*" OR url="*javascript:*") AND dest_host="icinga_web_server"