Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-4329

HIGH · 7.2 CVSS v3.1 Published 2026-03-26

Mitigation only

No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.

See remediation →

81/100

Remediation priority · High

Remotely reachable No privileges Zero-click

Official description

NVD · unedited

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.

Technical summary

dbcve analysis · high confidence

The Blackhole for Bad Bots WordPress plugin versions up to 3.8 stores User-Agent data using sanitize_text_field() which strips HTML tags but leaves quotes unescaped. When administrators view the Bad Bots log page, this stored data is rendered directly into HTML input value attributes (without esc_attr()) and span content (without esc_html()), allowing unauthenticated attackers to inject persistent JavaScript via a crafted User-Agent header.

MitigationApply esc_attr() when outputting data into HTML input value attributes and esc_html() when outputting into HTML span content on lines 75-83 of the plugin. Consider using more robust sanitization like sanitize_text_field() combined with additional entity encoding, or implementing output escaping at the point of display.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown

From the vector

Attack vector: Network
Complexity: Low
Privileges: None
User interaction: None
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Am I affected?

dbcve checks

Work through these to decide whether this CVE applies to you.

Confirm plugin installation

Navigate to WordPress admin dashboard > Plugins and locate Blackhole for Bad Bots in the installed plugins list

Affected if Plugin is not present in the installation
Check plugin version number

On the Plugins page, click on the Blackhole for Bad Bots plugin to view its details, or access the main plugin PHP file and locate the Version header in the plugin metadata. Compare your version to 3.8

Affected if Installed version is 3.8 or lower (any version up to 3.8)
Verify Bad Bots log feature is active

Access the plugin settings page (typically under Settings > Blackhole) and confirm that bot logging or the Bad Bots log functionality is enabled and capturing data

Affected if Logging is disabled - the vulnerability cannot be triggered without logged bot data
Inspect Bad Bots log page HTML output

View the Bad Bots log page in the WordPress admin panel, then use browser developer tools or view page source to examine how User-Agent strings are rendered in HTML input value attributes and span elements around lines 75-83 of the plugin file

Affected if User-Agent data is rendered without esc_attr() wrapping in input values OR without esc_html() wrapping in span content

You are affected if the Blackhole for Bad Bots plugin version 3.8 or lower is installed with bot logging enabled and the Bad Bots log page renders User-Agent data without proper HTML escaping functions.

Generated from the published advisory. Verify against your own configuration.

Remediation

From vendor data

Mitigation available No clean upgrade yet — mitigate in the meantime

Mitigation

Apply esc_attr() when outputting data into HTML input value attributes and esc_html() when outputting into HTML span content on lines 75-83 of the plugin. Consider using more robust sanitization like sanitize_text_field() combined with additional entity encoding, or implementing output escaping at the point of display.

Have this fixed Scoped from the published advisory

Consultation2.0 h
Implementation2.0 h
Testing3.0 h
Review / QA2.0 h

9.0 hours of engineering $1,570

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Scan for this in your stack

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References

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-4329 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2026-4329?

The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.

The version that genuinely resolved it — not the one the vendor claimed
A config change or rule that shut the vector down
A gotcha in the upgrade path that cost you an afternoon

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here

Verified mitigations, workarounds, and config changes
Version or environment caveats, and links to real fixes
No weaponised exploit code, or anything meant to cause harm
No spam, self-promotion, credentials, or personal data

At a glance

A fix existsA vendor remedy is published

Severity 7.2 High

Exploit likelihood EPSS, next 30 days 0.3%

Remediation

A high-priority fix

Have this fixed 9 hrs · Low

Typical engagement from $1,570

Get a fix See the full breakdown ↓

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2026-4329 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

Check your environment

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

CVSS breakdown

Am I affected?

Remediation

References