CVE-2025-13079
📋 TL;DR
This vulnerability allows unauthenticated attackers to unsubscribe arbitrary subscribers from mailing lists by brute-forcing predictable unsubscribe tokens. Attackers only need to know the victim's email address to exploit this authorization bypass. All WordPress sites using the Popup Builder plugin up to version 4.4.2 are affected.
💻 Affected Systems
- Popup Builder – Create highly converting, mobile friendly marketing popups 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
Mass unsubscription of all mailing list subscribers, disrupting email marketing campaigns and potentially violating privacy regulations by removing users without consent.
Likely Case
Targeted unsubscription of specific individuals from mailing lists, causing communication disruptions and potential data integrity issues.
If Mitigated
Limited impact with proper monitoring and quick response to detect unusual unsubscription patterns.
🎯 Exploit Status
Exploitation requires only knowledge of email addresses and predictable token generation, making brute-forcing straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.4.3 or later
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins → Installed Plugins. 3. Find Popup Builder plugin. 4. Click 'Update Now' if update is available. 5. Alternatively, download version 4.4.3+ from WordPress repository and manually update.
🔧 Temporary Workarounds
Disable Popup Builder Plugin
allTemporarily disable the vulnerable plugin until patched
wp plugin deactivate popup-builder
Restrict Access to Unsubscribe Endpoints
linuxUse web application firewall or .htaccess to block access to unsubscribe functionality
# Add to .htaccess: RewriteRule ^wp-content/plugins/popup-builder.*unsubscribe - [F]
🧯 If You Can't Patch
- Implement rate limiting on unsubscribe endpoints to prevent brute-force attacks
- Monitor unsubscribe logs for unusual patterns and implement alerting
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin → Plugins → Installed Plugins → Popup Builder version. If version is 4.4.2 or lower, you are vulnerable.Check Version:
wp plugin get popup-builder --field=versionVerify Fix Applied:
Verify plugin version is 4.4.3 or higher in WordPress admin panel.📡 Detection & Monitoring
Log Indicators:
- Unusual spike in unsubscribe requests
- Multiple failed unsubscribe attempts from same IP
- Unsubscribe requests for email addresses not in database
Network Indicators:
- High volume of POST requests to unsubscribe endpoints
- Patterned requests to /wp-content/plugins/popup-builder/ endpoints
SIEM Query:
source="wordpress.log" AND ("unsubscribe" OR "popup-builder") AND status=200 | stats count by src_ip🔗 References
- https://plugins.trac.wordpress.org/browser/popup-builder/tags/4.4.2/com/classes/Actions.php#L842
- https://plugins.trac.wordpress.org/browser/popup-builder/tags/4.4.2/com/helpers/AdminHelper.php#L896
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3444540%40popup-builder&new=3444540%40popup-builder&sfp_email=&sfph_mail=
- https://www.wordfence.com/threat-intel/vulnerabilities/id/62b29721-0580-4e1d-824d-9b8355890248?source=cve
