What’s Vulnerable › Vulnerabilities

CVE-2026-4329: Blackhole for Bad Bots <= 3.8 - Unauthenticated Stored Cross-Site Scripting via User-Agent HTTP Header

• Severity: high (CVSS 7.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-26 · updated 2026-06-17
• Weakness: CWE-79

Description

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

• Blackhole for Bad Bots: through 3.8

References

• https://plugins.trac.wordpress.org/browser/blackhole-bad-bots/tags/3.8/inc/badbots-register.php#L75
• https://plugins.trac.wordpress.org/browser/blackhole-bad-bots/tags/3.8/inc/badbots-register.php#L79
• https://plugins.trac.wordpress.org/browser/blackhole-bad-bots/tags/3.8/inc/badbots-register.php#L85
• https://plugins.trac.wordpress.org/browser/blackhole-bad-bots/tags/3.8/inc/blackhole-core.php#L180
• https://plugins.trac.wordpress.org/browser/blackhole-bad-bots/tags/3.8/inc/blackhole-helpers.php#L22
• https://plugins.trac.wordpress.org/browser/blackhole-bad-bots/trunk/inc/badbots-register.php#L75
• https://plugins.trac.wordpress.org/browser/blackhole-bad-bots/trunk/inc/badbots-register.php#L79
• https://plugins.trac.wordpress.org/browser/blackhole-bad-bots/trunk/inc/badbots-register.php#L85
• https://plugins.trac.wordpress.org/browser/blackhole-bad-bots/trunk/inc/blackhole-core.php#L180
• https://plugins.trac.wordpress.org/browser/blackhole-bad-bots/trunk/inc/blackhole-helpers.php#L22
• https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3487350%40blackhole-bad-bots&new=3487350%40blackhole-bad-bots&sfp_email=&sfph_mail=
• https://www.wordfence.com/threat-intel/vulnerabilities/id/a71992e2-fdac-4e89-8867-4b771d9b4374?source=cve

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