CVE-2025-63593
📋 TL;DR
Grav CMS version 1.7.49.5 contains a cross-site scripting (XSS) vulnerability that allows attackers to inject malicious scripts into web pages viewed by other users. This affects all Grav CMS installations running the vulnerable version. Users who access compromised pages may have their sessions hijacked or sensitive information stolen.
💻 Affected Systems
- Grav CMS
📦 What is this software?
Grav by Getgrav
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal administrator credentials, take over administrative accounts, deface websites, or redirect users to malicious sites, potentially leading to complete system compromise.
Likely Case
Attackers inject malicious scripts to steal user session cookies or credentials, perform actions on behalf of authenticated users, or deliver malware through the compromised website.
If Mitigated
With proper input validation and output encoding, the impact is limited to potential data leakage from users who interact with malicious content, but system integrity remains intact.
🎯 Exploit Status
XSS vulnerabilities are commonly exploited and weaponization is likely given the public proof-of-concept.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.7.49.6 or later
Vendor Advisory: https://github.com/getgrav/grav/releases/tag/1.7.49.5
Restart Required: No
Instructions:
1. Backup your current Grav installation. 2. Update Grav CMS to version 1.7.49.6 or later via the admin panel or command line. 3. Clear any caches. 4. Verify the update was successful.
🔧 Temporary Workarounds
Input Validation Filter
allImplement server-side input validation to sanitize user inputs before processing.
Content Security Policy
allImplement a strict Content Security Policy header to mitigate XSS impact.
Add to .htaccess or web server config: Header set Content-Security-Policy "default-src 'self'; script-src 'self'"
Add to Nginx config: add_header Content-Security-Policy "default-src 'self'; script-src 'self'";
🧯 If You Can't Patch
- Implement a Web Application Firewall (WAF) with XSS protection rules enabled.
- Disable user input fields or forms that may be vulnerable until patching is possible.
🔍 How to Verify
Check if Vulnerable:
Check your Grav CMS version by viewing the admin panel dashboard or running: php bin/grav versionCheck Version:
php bin/grav versionVerify Fix Applied:
After updating, verify the version shows 1.7.49.6 or higher using: php bin/grav version📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests with script tags or JavaScript payloads in parameters
- Multiple failed login attempts from unexpected locations following suspicious requests
Network Indicators:
- HTTP requests containing <script> tags or JavaScript code in URL parameters or form data
- Outbound connections to suspicious domains from your web server
SIEM Query:
source="web_server_logs" AND (http_request="*<script>*" OR http_request="*javascript:*" OR http_request="*onload=*" OR http_request="*onerror=*")