CVE-2025-8871
📋 TL;DR
The Everest Forms Pro WordPress plugin is vulnerable to PHP object injection via deserialization of untrusted input in the mime_content_type() function. Unauthenticated attackers can exploit this when a form contains a non-required signature field and an image upload field. This vulnerability only has impact if another plugin or theme with a POP chain is installed, and it only affects PHP versions prior to 8.
💻 Affected Systems
- Everest Forms Pro 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
If combined with a POP chain from another plugin/theme, attackers could execute arbitrary code, delete files, or retrieve sensitive data leading to complete system compromise.
Likely Case
No impact unless another vulnerable plugin/theme with a POP chain is installed; most sites will see no exploitation due to lack of POP chains.
If Mitigated
With PHP 8+ or no additional vulnerable plugins/themes, the vulnerability has no practical impact despite its presence.
🎯 Exploit Status
Exploitation requires specific form configuration and depends on presence of POP chains in other software; no known weaponized exploits exist.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version after 1.9.7
Vendor Advisory: https://everestforms.net/changelog/
Restart Required: No
Instructions:
1. Update Everest Forms Pro plugin to latest version via WordPress admin panel. 2. Verify update to version >1.9.7. 3. No server restart needed.
🔧 Temporary Workarounds
Upgrade PHP to version 8 or higher
linuxThe vulnerability is only exploitable in PHP versions prior to 8; upgrading PHP mitigates the issue.
# Update PHP via package manager (example for Ubuntu/Debian)
sudo apt update && sudo apt install php8.2
# Restart web server
sudo systemctl restart apache2
Remove vulnerable form configurations
allTemporarily remove or disable forms containing non-required signature fields combined with image upload fields.
🧯 If You Can't Patch
- Upgrade PHP to version 8 or higher immediately.
- Audit and remove any unnecessary plugins/themes that might contain POP chains to reduce attack surface.
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin > Plugins > Everest Forms Pro version. If version ≤1.9.7 and PHP <8, site is vulnerable.Check Version:
wp plugin list --name=everest-forms-pro --field=versionVerify Fix Applied:
Verify Everest Forms Pro version >1.9.7 in WordPress admin and confirm PHP version ≥8 via phpinfo() or command line.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to Everest Forms endpoints with serialized data in parameters.
- PHP warnings/errors related to deserialization in web server logs.
Network Indicators:
- HTTP requests containing serialized PHP objects in form submissions.
SIEM Query:
source="web_logs" AND uri_path="/wp-admin/admin-ajax.php" AND (param="mime_content_type" OR data CONTAINS "O:")