# CVE-2026-9643: WP Meta SEO <= 4.5.18 - Unauthenticated Stored Cross-Site Scripting via REQUEST_URI in 404 Logging

> Unauthenticated attackers can inject scripts via 404 logging that execute when administrators view the plugin's admin page.

- **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:** 24 Jun 2026
- **Updated:** 29 Jun 2026
- **Also known as:** GHSA-qhjr-7q98-w4h3

## What is CVE-2026-9643?

CVE-2026-9643 is a high-severity cross-site scripting vulnerability in joomunited WP Meta SEO, published on 24 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The WP Meta SEO plugin for WordPress is vulnerable to Unauthenticated Stored Cross-Site Scripting via the REQUEST_URI server variable in all versions up to, and including, 4.5.18. When the plugin's `wpmsTemplateRedirect()` hook detects a 404, it concatenates `$_SERVER['HTTP_HOST']` with the raw `$_SERVER['REQUEST_URI']` and inserts that value verbatim into the `wp_wpms_links.link_url` column via `$wpdb->insert()`. This makes it possible for unauthenticated attackers to inject arbitrary web scripts that execute whenever an administrator views the plugin's 404 & Redirects admin page (`/wp-admin/admin.php?page=metaseo_broken_link`).

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

## Which versions are affected by CVE-2026-9643?


## How do I fix CVE-2026-9643?

No fix has been published for CVE-2026-9643 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-9643 being exploited?

There is no known exploitation of CVE-2026-9643 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9643 and fix it if it is affected.

What it is: CVE-2026-9643 is a high-severity cross-site scripting vulnerability in joomunited WP Meta SEO, published on 24 Jun 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-2026-9643 in the wild and no public exploit code.

Affected product: joomunited WP Meta SEO. 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-2026-9643/ (Markdown: https://insights.sbomify.com/CVE-2026-9643/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9643
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9643
- OSV: https://osv.dev/vulnerability/CVE-2026-9643

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-9643/
Summaries are generated and may contain mistakes; the official description above is the record.