CVE-2025-27825
📋 TL;DR
This Cross-Site Scripting (XSS) vulnerability in the Bootstrap 5 Lite theme for Backdrop CMS allows attackers to inject malicious scripts into web pages viewed by other users. It affects Backdrop CMS installations using the Bootstrap 5 Lite theme before version 1.x-1.0.3. The vulnerability occurs due to insufficient sanitization of certain class names.
💻 Affected Systems
- Backdrop CMS Bootstrap 5 Lite theme
⚠️ 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 session cookies, perform actions as authenticated users, deface websites, or redirect users to malicious sites, potentially leading to complete account compromise.
Likely Case
Attackers inject malicious JavaScript to steal user session cookies or credentials, potentially gaining unauthorized access to user accounts.
If Mitigated
With proper Content Security Policy (CSP) headers and input validation, impact is limited to the specific vulnerable page element.
🎯 Exploit Status
XSS vulnerabilities typically have low exploitation complexity. The advisory suggests the vulnerability can be exploited without authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.x-1.0.3
Vendor Advisory: https://backdropcms.org/security/backdrop-sa-contrib-2025-004
Restart Required: No
Instructions:
1. Log into your Backdrop CMS admin panel. 2. Navigate to Appearance > Update. 3. Check for available updates. 4. Update Bootstrap 5 Lite theme to version 1.x-1.0.3 or later. 5. Clear all caches from Configuration > Development > Performance.
🔧 Temporary Workarounds
Apply manual sanitization patch
allManually patch the vulnerable theme files to sanitize class name inputs
# Backup theme files first
# Edit the vulnerable PHP files to add proper sanitization
# See vendor advisory for specific file locations
Switch to alternative theme
allTemporarily switch to a different theme while waiting for patch
1. Navigate to Appearance in Backdrop admin
2. Disable Bootstrap 5 Lite theme
3. Enable a different, secure theme
🧯 If You Can't Patch
- Implement strict Content Security Policy (CSP) headers to limit script execution
- Deploy a Web Application Firewall (WAF) with XSS protection rules
🔍 How to Verify
Check if Vulnerable:
Check the theme version in Backdrop CMS admin panel under Appearance > Update or by examining the theme's .info fileCheck Version:
Check the theme's .info file in sites/all/themes/bootstrap5_lite/bootstrap5_lite.info for version numberVerify Fix Applied:
Confirm Bootstrap 5 Lite theme version is 1.x-1.0.3 or later in the admin panel📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests containing script tags or JavaScript in class name parameters
- Multiple failed attempts to access theme files
Network Indicators:
- HTTP requests with suspicious JavaScript payloads in query parameters or POST data
SIEM Query:
web_access_logs WHERE (url CONTAINS "<script>" OR url CONTAINS "javascript:") AND url CONTAINS "bootstrap5_lite"