CVE-2025-66103
📋 TL;DR
This DOM-based Cross-Site Scripting (XSS) vulnerability in the WPCal.Io WordPress plugin allows attackers to inject malicious scripts that execute in users' browsers when they visit compromised pages. The vulnerability affects all WPCal.Io plugin versions up to 0.9.5.9, potentially impacting any WordPress site using this plugin.
💻 Affected Systems
- WPCal.Io WordPress 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 administrator session cookies, perform actions as authenticated users, deface websites, or redirect users to malicious sites, potentially leading to complete site compromise.
Likely Case
Attackers inject malicious scripts to steal user session cookies or credentials, perform unauthorized actions, or redirect users to phishing pages.
If Mitigated
With proper Content Security Policy (CSP) headers and input validation, the impact is limited to the specific vulnerable page component.
🎯 Exploit Status
DOM-based XSS typically requires user interaction but can be exploited through crafted URLs or forms.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.9.5.10 or later
Vendor Advisory: https://patchstack.com/database/wordpress/plugin/wpcal/vulnerability/wordpress-wpcal-io-plugin-0-9-5-9-cross-site-scripting-xss-vulnerability?_s_id=cve
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins > Installed Plugins. 3. Find WPCal.Io plugin. 4. Click 'Update Now' if update is available. 5. Alternatively, download latest version from WordPress repository and manually update.
🔧 Temporary Workarounds
Disable WPCal.Io Plugin
allTemporarily disable the vulnerable plugin until patched.
wp plugin deactivate wpcal
Implement Content Security Policy
allAdd CSP headers to mitigate XSS attacks.
Add to .htaccess: 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
- Disable WPCal.Io plugin immediately
- Implement web application firewall (WAF) with XSS protection rules
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin > Plugins > Installed Plugins for WPCal.Io version. If version is 0.9.5.9 or lower, you are vulnerable.Check Version:
wp plugin get wpcal --field=versionVerify Fix Applied:
Verify WPCal.Io plugin version is 0.9.5.10 or higher in WordPress admin panel.📡 Detection & Monitoring
Log Indicators:
- Unusual POST/GET requests to WPCal.Io endpoints with script tags
- Multiple failed XSS attempts in web server logs
Network Indicators:
- HTTP requests containing script injection patterns to WPCal.Io URLs
SIEM Query:
source="web_server" AND (uri="*wpcal*" AND (body="*<script>*" OR uri="*javascript:*"))