CVE-2025-12846
📋 TL;DR
The Blocksy Companion WordPress plugin allows authenticated users with author privileges or higher to upload arbitrary files due to insufficient SVG file validation. Attackers can bypass security checks using double extension files, potentially leading to remote code execution. All WordPress sites using Blocksy Companion up to version 2.1.19 are affected.
💻 Affected Systems
- Blocksy Companion 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
Authenticated attackers gain remote code execution, leading to complete site compromise, data theft, malware distribution, or server takeover.
Likely Case
Attackers upload malicious files to establish persistence, deface websites, or steal sensitive data from vulnerable WordPress installations.
If Mitigated
With proper file upload restrictions and user privilege controls, impact is limited to unauthorized file storage without execution.
🎯 Exploit Status
Exploitation requires authenticated access but is straightforward once attacker has author credentials.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.1.20 or later
Vendor Advisory: https://plugins.trac.wordpress.org/changeset/3391933/blocksy-companion/trunk/framework/features/svg.php
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins → Installed Plugins. 3. Find Blocksy Companion and click 'Update Now'. 4. Verify version is 2.1.20 or higher.
🔧 Temporary Workarounds
Disable SVG uploads via .htaccess
linuxPrevent SVG file uploads at web server level
Add to .htaccess: <FilesMatch "\.svg$">
Order allow,deny
Deny from all
</FilesMatch>
Restrict author user creation
allLimit creation of author-level accounts to trusted administrators
🧯 If You Can't Patch
- Immediately disable or remove the Blocksy Companion plugin
- Implement strict file upload filtering at web application firewall level
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin → Plugins → Installed Plugins for Blocksy Companion version 2.1.19 or lowerCheck Version:
wp plugin list --name=blocksy-companion --field=versionVerify Fix Applied:
Confirm Blocksy Companion version is 2.1.20 or higher in WordPress admin panel📡 Detection & Monitoring
Log Indicators:
- Unusual SVG file uploads via wp-admin/upload.php
- Multiple failed upload attempts with double extensions
- Author-level users uploading executable file types
Network Indicators:
- POST requests to /wp-admin/async-upload.php with SVG payloads
- Unusual file upload traffic from author accounts
SIEM Query:
source="wordpress.log" AND ("upload.php" OR "async-upload") AND ("svg" OR "double extension")