CVE-2025-31423
📋 TL;DR
CVE-2025-31423 is a PHP object injection vulnerability in the Umberto WordPress theme that allows attackers to execute arbitrary code by exploiting insecure deserialization. This affects all WordPress sites using Umberto theme versions up to 1.2.8. Attackers can potentially take full control of vulnerable websites.
💻 Affected Systems
- AncoraThemes Umberto WordPress 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
Complete compromise of the WordPress site leading to data theft, defacement, malware distribution, and server takeover.
Likely Case
Remote code execution allowing attackers to create backdoors, steal sensitive data, and pivot to other systems.
If Mitigated
Limited impact if proper input validation and output encoding are implemented, though deserialization vulnerabilities remain dangerous.
🎯 Exploit Status
Public exploit details available on Patchstack. Deserialization vulnerabilities are commonly weaponized in WordPress ecosystems.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.2.9 or later
Vendor Advisory: https://patchstack.com/database/wordpress/theme/umberto/vulnerability/wordpress-umberto-1-2-8-php-object-injection-vulnerability?_s_id=cve
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Appearance > Themes. 3. Check for Umberto theme updates. 4. Update to version 1.2.9 or later. 5. If no update available, remove the theme immediately.
🔧 Temporary Workarounds
Disable Umberto Theme
allSwitch to a different WordPress theme to remove the vulnerable component
wp theme deactivate umberto
wp theme activate twentytwentyfour
Input Validation Filter
allAdd custom PHP filter to sanitize deserialization inputs (temporary measure)
Add to theme's functions.php: add_filter('pre_deserialize', 'sanitize_untrusted_data');
🧯 If You Can't Patch
- Immediately deactivate and remove the Umberto theme from all WordPress installations
- Implement web application firewall (WAF) rules to block deserialization attempts and monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin panel > Appearance > Themes for Umberto theme version. If version is 1.2.8 or lower, you are vulnerable.Check Version:
wp theme list --name=umberto --field=versionVerify Fix Applied:
Verify Umberto theme version is 1.2.9 or higher in WordPress admin panel, or confirm theme is completely removed.📡 Detection & Monitoring
Log Indicators:
- Unusual PHP deserialization errors in WordPress debug logs
- Suspicious POST requests to theme-related endpoints
- Unexpected file creation in wp-content/themes/umberto/
Network Indicators:
- HTTP requests containing serialized PHP objects in parameters
- Traffic to Umberto theme files with unusual payloads
SIEM Query:
source="wordpress.log" AND ("deserialize" OR "unserialize" OR "umberto") AND status=500