CVE-2026-0691
📋 TL;DR
This stored XSS vulnerability in the CM E-Mail Blacklist WordPress plugin allows authenticated administrators to inject malicious scripts that execute when users view affected pages. Only WordPress multi-site installations and sites with unfiltered_html disabled are affected. Attackers can steal session cookies, redirect users, or perform actions on their behalf.
💻 Affected Systems
- CM E-Mail Blacklist 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
Administrator account compromise leading to full site takeover, data theft, malware distribution to visitors, and credential harvesting.
Likely Case
Session hijacking of other administrators or users, defacement of admin pages, or redirection to malicious sites.
If Mitigated
Limited impact due to requiring admin privileges and specific WordPress configurations; primarily affects admin interface.
🎯 Exploit Status
Requires administrator-level WordPress access. Exploitation is straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 1.6.2
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins → Installed Plugins. 3. Find 'CM E-Mail Blacklist'. 4. Click 'Update Now' if available, or delete and reinstall latest version. 5. Verify plugin version is >1.6.2.
🔧 Temporary Workarounds
Disable Plugin
allTemporarily disable the vulnerable plugin until patched.
wp plugin deactivate cm-email-blacklist
Enable unfiltered_html
allFor single-site installations, enable unfiltered_html capability for administrators (not recommended for security).
Add define('DISALLOW_UNFILTERED_HTML', false); to wp-config.php
🧯 If You Can't Patch
- Remove administrator access from untrusted users immediately.
- Implement web application firewall (WAF) rules to block XSS payloads in black_email parameter.
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin → Plugins → Installed Plugins for CM E-Mail Blacklist version ≤1.6.2.Check Version:
wp plugin get cm-email-blacklist --field=versionVerify Fix Applied:
Confirm plugin version is >1.6.2 in WordPress admin panel.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /wp-admin/admin.php?page=cm-email-blacklist with script tags in parameters
- Multiple failed login attempts followed by successful admin login
Network Indicators:
- HTTP requests containing <script> tags in black_email parameter to WordPress admin endpoints
SIEM Query:
source="wordpress.log" AND (uri_path="/wp-admin/admin.php" AND query_string="*page=cm-email-blacklist*" AND (post_data="*black_email=*<script>*" OR post_data="*black_email=*javascript:*"))🔗 References
- https://plugins.trac.wordpress.org/browser/cm-email-blacklist/tags/1.6.2/backend/views/settings/email_blacklist.phtml#L67
- https://plugins.trac.wordpress.org/browser/cm-email-blacklist/trunk/backend/views/settings/email_blacklist.phtml#L67
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3440158%40cm-email-blacklist&new=3440158%40cm-email-blacklist&sfp_email=&sfph_mail=
- https://www.wordfence.com/threat-intel/vulnerabilities/id/821f4ea9-bc25-4d65-9058-5b77c4f1b230?source=cve
