# CVE-2026-9643: JoomUnited WP Meta SEO unauthenticated stored XSS in 404 handler

Source: https://junglewise.ai/threats/cve-2026-9643-joomunited-wp-meta-seo-unauthenticated-stored-xss-in-404-handler  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-24. Updated: 2026-06-24  
License: CC BY 4.0 with a link back

CVE-2026-9643 · Severity: high · CVSS 7.2 · Published 2026-06-24

WP Meta SEO is a WordPress plugin used to manage search engine optimization and monitor broken links. A security flaw allows unauthenticated visitors to inject malicious scripts into the plugin's database by simply visiting a non-existent page on the site. These scripts are then executed in the browser of a site administrator when they view the plugin's broken link report, potentially leading to unauthorized administrative actions or site takeover.

Vendors: [JoomUnited](https://junglewise.ai/threats/vendors/joomunited).

## Quick answers

**Is CVE-2026-9643 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-9643 being exploited in the wild.

**How severe is CVE-2026-9643?** High severity, with a CVSS score of 7.2, published 24 June 2026.

**Which products and versions are affected?** JoomUnited WP Meta SEO up to, and including, 4.5.18.

**Is there a fix for CVE-2026-9643?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-9643 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-9643?** Check whether you run JoomUnited WP Meta SEO at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a stored Cross-Site Scripting (XSS) issue within the wpmsTemplateRedirect() hook. When the plugin detects a 404 error, it captures the raw $_SERVER['REQUEST_URI'] and concatenates it with $_SERVER['HTTP_HOST'], inserting the resulting string directly into the wp_wpms_links.link_url database column without sanitization. Because this data is later rendered without escaping on the '404 & Redirects' admin page, an unauthenticated attacker can craft a URL containing a malicious payload. When an administrator accesses the report at /wp-admin/admin.php?page=metaseo_broken_link, the payload executes in their session context. The issue is addressed in versions following 4.5.18.

## Affected products

- JoomUnited WP Meta SEO up to, and including, 4.5.18

## Timeline

- 2026-06-24: disclosed
- 2026-06-24: advisory

## References

- [https://plugins.trac.wordpress.org/browser/wp-meta-seo/tags/4.5.18/inc/class.metaseo-broken-link-table.php](https://plugins.trac.wordpress.org/browser/wp-meta-seo/tags/4.5.18/inc/class.metaseo-broken-link-table.php)
- [https://plugins.trac.wordpress.org/browser/wp-meta-seo/tags/4.5.18/wp-meta-seo.php](https://plugins.trac.wordpress.org/browser/wp-meta-seo/tags/4.5.18/wp-meta-seo.php)
- [https://plugins.trac.wordpress.org/browser/wp-meta-seo/tags/4.5.18/wp-meta-seo.php](https://plugins.trac.wordpress.org/browser/wp-meta-seo/tags/4.5.18/wp-meta-seo.php)
- [https://plugins.trac.wordpress.org/changeset?old_path=/wp-meta-seo/tags/4.5.12&new_path=/wp-meta-seo/tags/4.5.13](https://plugins.trac.wordpress.org/changeset?old_path=/wp-meta-seo/tags/4.5.12&new_path=/wp-meta-seo/tags/4.5.13)
- [https://ti.wordfence.io/vulnerabilities/ca91e41d-b728-4eb0-86d5-043813d8c2c1](https://ti.wordfence.io/vulnerabilities/ca91e41d-b728-4eb0-86d5-043813d8c2c1)
- [https://www.wordfence.com/threat-intel/vulnerabilities/id/beceb218-34bf-4571-a07b-939abc7ead8e?source=cve](https://www.wordfence.com/threat-intel/vulnerabilities/id/beceb218-34bf-4571-a07b-939abc7ead8e?source=cve)

## Related threats

- [JoomUnited WP Meta SEO SSRF via new_link parameter](https://junglewise.ai/threats/cve-2026-11370-joomunited-wp-meta-seo-ssrf-via-new-link-parameter)