CVE-2025-27337
📋 TL;DR
This vulnerability allows attackers to inject malicious scripts into web pages generated by the Fontsampler WordPress plugin, which are then executed in victims' browsers. It affects all WordPress sites using Fontsampler plugin versions up to 0.4.14. The attack is reflected, meaning the malicious script comes from the current request rather than being stored on the server.
💻 Affected Systems
- WordPress Fontsampler plugin
⚠️ 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, redirect users to malicious sites, perform actions on behalf of authenticated users, or deface websites.
Likely Case
Attackers craft malicious links containing XSS payloads and trick users into clicking them, leading to session hijacking or credential theft.
If Mitigated
With proper input validation and output encoding, malicious scripts are neutralized before reaching users' browsers.
🎯 Exploit Status
XSS vulnerabilities are commonly exploited and require minimal technical skill.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.4.15 or later
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins > Installed Plugins. 3. Find Fontsampler and click 'Update Now'. 4. Verify version is 0.4.15 or higher.
🔧 Temporary Workarounds
Disable Fontsampler plugin
allTemporarily disable the vulnerable plugin until patched
wp plugin deactivate fontsampler
Implement WAF rules
allAdd web application firewall rules to block XSS payloads
🧯 If You Can't Patch
- Implement Content Security Policy (CSP) headers to restrict script execution
- Use input validation and output encoding in custom code that interacts with Fontsampler
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin panel > Plugins > Fontsampler version. If version is 0.4.14 or lower, you are vulnerable.Check Version:
wp plugin get fontsampler --field=versionVerify Fix Applied:
After updating, verify Fontsampler version shows 0.4.15 or higher in WordPress plugins list.📡 Detection & Monitoring
Log Indicators:
- Unusual GET/POST requests containing script tags or JavaScript code in parameters
- Multiple failed XSS attempts in web server logs
Network Indicators:
- HTTP requests with suspicious parameters containing <script>, javascript:, or encoded payloads
SIEM Query:
source="web_server_logs" AND ("<script" OR "javascript:" OR "%3Cscript" OR "%22onload%22")