CVE-2025-31604
📋 TL;DR
This vulnerability allows attackers to inject malicious scripts into Cal.com web pages, which execute when other users view those pages. It affects all Cal.com installations up to version 1.0.0. Users who view compromised pages could have their sessions hijacked or sensitive data stolen.
💻 Affected Systems
- Cal.com 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 credentials, take over 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, perform actions on behalf of users, or redirect to phishing pages.
If Mitigated
With proper input validation and output encoding, the XSS payloads would be neutralized before reaching users, preventing exploitation.
🎯 Exploit Status
Stored XSS vulnerabilities are commonly exploited. While no public PoC is documented, the vulnerability type is well-understood and easy to weaponize.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 1.0.0
Vendor Advisory: https://patchstack.com/database/wordpress/plugin/cal-com/vulnerability/wordpress-cal-com-plugin-1-0-0-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 Cal.com plugin. 4. Click 'Update Now' if update available. 5. If no update available, deactivate and remove plugin until patched version is released.
🔧 Temporary Workarounds
Disable Cal.com plugin
allTemporarily disable the vulnerable plugin until patched version is available
wp plugin deactivate cal-com
Implement WAF rules
allAdd web application firewall rules to block XSS payloads targeting Cal.com endpoints
🧯 If You Can't Patch
- Implement Content Security Policy (CSP) headers to restrict script execution
- Enable input validation and output encoding at the application level for all user inputs
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin panel → Plugins → Cal.com version. If version is 1.0.0 or earlier, you are vulnerable.Check Version:
wp plugin get cal-com --field=versionVerify Fix Applied:
After updating, verify Cal.com plugin version is higher than 1.0.0 in WordPress admin panel.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to Cal.com endpoints with script tags in parameters
- Multiple failed XSS attempts in web server logs
Network Indicators:
- HTTP requests containing <script> tags or javascript: URIs targeting Cal.com paths
SIEM Query:
source="web_server_logs" AND (uri_path="*cal-com*" AND (message="*<script>*" OR message="*javascript:*"))