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

> Unauthenticated attackers can inject scripts via User-Agent headers that execute when admins view the plugin's log page, potentially leading to account takeover.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Mar 2026
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-cpmh-vq2q-hhp7

## What is CVE-2026-4329?

CVE-2026-4329 is a high-severity cross-site scripting vulnerability in specialk Blackhole for Bad Bots, published on 26 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-4329?


## How do I fix CVE-2026-4329?

No fix has been published for CVE-2026-4329 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4329 being exploited?

There is no known exploitation of CVE-2026-4329 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4329 and fix it if it is affected.

What it is: CVE-2026-4329 is a high-severity cross-site scripting vulnerability in specialk Blackhole for Bad Bots, published on 26 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-4329 in the wild and no public exploit code.

Affected product: specialk Blackhole for Bad Bots. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-4329/ (Markdown: https://insights.sbomify.com/CVE-2026-4329/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4329
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4329
- OSV: https://osv.dev/vulnerability/CVE-2026-4329

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4329/
Summaries are generated and may contain mistakes; the official description above is the record.