CVE-2025-39565
📋 TL;DR
A PHP object injection vulnerability in Melapress Login Security WordPress plugin allows attackers to execute arbitrary code through deserialization of untrusted data. This affects all WordPress sites using the plugin versions up to 2.1.0. Attackers can potentially gain unauthorized access and control over affected websites.
💻 Affected Systems
- Melapress Login Security WordPress Plugin
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete site compromise, data theft, malware installation, or website defacement.
Likely Case
Unauthorized administrative access, privilege escalation, or backdoor installation on vulnerable WordPress sites.
If Mitigated
Limited impact if proper input validation and security controls prevent exploitation attempts.
🎯 Exploit Status
Deserialization vulnerabilities are commonly exploited in WordPress environments. While no public PoC exists, similar vulnerabilities are frequently weaponized.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.1.1 or later
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins > Installed Plugins. 3. Find Melapress Login Security. 4. Click 'Update Now' if available. 5. Alternatively, download latest version from WordPress repository and manually update.
🔧 Temporary Workarounds
Disable Plugin
allTemporarily disable the vulnerable plugin until patched
wp plugin deactivate melapress-login-security
Restrict Access
allImplement web application firewall rules to block suspicious deserialization attempts
🧯 If You Can't Patch
- Implement strict input validation and sanitization for all user inputs
- Deploy web application firewall with rules targeting PHP object injection patterns
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin panel > Plugins > Melapress Login Security versionCheck Version:
wp plugin get melapress-login-security --field=versionVerify Fix Applied:
Verify plugin version is 2.1.1 or higher in WordPress admin📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to WordPress admin-ajax.php or admin-post.php
- PHP serialized data in unexpected locations
- Failed authentication attempts followed by unusual activity
Network Indicators:
- HTTP requests containing serialized PHP objects (O:)
- Suspicious traffic to /wp-admin/admin-ajax.php
SIEM Query:
source="wordpress.log" AND ("melapress" OR "admin-ajax.php") AND ("serialize" OR "unserialize" OR "O:")