CVE-2025-31919
📋 TL;DR
CVE-2025-31919 is a PHP object injection vulnerability in the Spare WordPress theme that allows attackers to execute arbitrary code through deserialization of untrusted data. This affects all WordPress sites using Spare theme versions up to 1.7. Attackers can exploit this to gain complete control over affected websites.
💻 Affected Systems
- WordPress Spare 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
Remote code execution leading to complete website compromise, data theft, malware installation, and server takeover.
Likely Case
Website defacement, backdoor installation, credential theft, and unauthorized administrative access.
If Mitigated
Limited impact if proper input validation and deserialization controls are implemented.
🎯 Exploit Status
Public exploit details available on security research sites. Simple HTTP requests can trigger the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version after 1.7 (check for latest update)
Vendor Advisory: https://patchstack.com/database/wordpress/theme/spare/vulnerability/wordpress-spare-1-7-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 Spare theme updates. 4. Update to latest version. 5. If no update available, remove Spare theme and replace with secure alternative.
🔧 Temporary Workarounds
Disable Spare Theme
allSwitch to a different WordPress theme to remove the vulnerable component
WordPress Admin: Appearance > Themes > Activate alternative theme
WAF Rule Implementation
allBlock malicious deserialization attempts with web application firewall
Add WAF rule to block requests containing serialized PHP objects in parameters
🧯 If You Can't Patch
- Implement strict input validation on all user-controlled data
- Deploy web application firewall with deserialization attack detection
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin panel: Appearance > Themes. If Spare theme is installed and version is 1.7 or earlier, system is vulnerable.Check Version:
WordPress Admin: Appearance > Themes, or check /wp-content/themes/spare/style.css for version headerVerify Fix Applied:
Verify Spare theme version is greater than 1.7 in WordPress admin panel. Test with security scanner for PHP object injection vulnerabilities.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to WordPress endpoints
- PHP errors related to unserialize() function
- Unexpected file writes in wp-content directory
Network Indicators:
- HTTP requests containing serialized PHP objects (O:)
- Requests to unusual WordPress admin-ajax.php endpoints
SIEM Query:
source="wordpress.log" AND ("unserialize" OR "O:" OR "C:" OR "a:" in request_body)