CVE-2026-4329: Specialk Blackhole For Bad Bots

High severity, CVSS 7.2. EPSS: 0.5% chance of exploitation in the next 30 days.

The Blackhole for Bad Bots plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the User-Agent HTTP header in all versions up to and including 3.8. This is due to insufficient input sanitization and output escaping. The plugin uses sanitize_text_field() when capturing bot data (which strips HTML tags but does not escape HTML entities like double quotes), then stores the data via update_option(). When an administrator views the Bad Bots log page, the stored data is output directly into HTML input value attributes (lines 75-83) without esc_attr() and into HTML span content without esc_html(). This makes it possible for unauthenticated attackers to inject arbitrary web scripts that execute when an administrator views the Blackhole Bad Bots admin page.

Affected products

• Specialk Blackhole For Bad Bots: up to and including 3.8

Published 2026-03-26. Last modified 2026-06-17.