Banhammer – Monitor Site Traffic, Block Bad Users and Bots <= 3.4.8 — Unauthenticated Protection Mechanism Bypass

Am I affected?

• Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Banhammer – Monitor Site Traffic, Block Bad Users and Bots.
• No admin access? Run a passive check of your site. It reads public files only.
• No account is needed to exploit this. Treat any exposed site on an affected version as at risk.

What to do

1. Update to version 3.4.9, or a newer patched version
2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
3. Watch Banhammer – Monitor Site Traffic, Block Bad Users and Bots to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to Jonas Benjamin Friedli.

The Banhammer – Monitor Site Traffic, Block Bad Users and Bots plugin for WordPress is vulnerable to Blocking Bypass in all versions up to, and including, 3.4.8. This is due to a site-wide “secret key” being deterministically generated from a constant character set using md5() and base64_encode() and then stored in the `banhammer_secret_key` option. This makes it possible for unauthenticated attackers to bypass the plugin’s logging and blocking by appending a GET parameter named `banhammer-process_{SECRET}` where `{SECRET}` is the predictable value, thereby causing Banhammer to abort its protections for that request.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

• Advisorywordfence.com

Timeline

1. Sep 25, 2025

   CVE published

   Severity medium, CVSS 5.3

2. Nov 13, 2026

   Record last updated