ZeM STL <= 1.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode Attributes

Summary

The ZeM STL plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the [zemstl] shortcode in all versions up to and including 1.0. This is due to insufficient input sanitization and output escaping on user-supplied shortcode attributes, specifically the 'url', 'color', and 'bgcolor' parameters. These attribute values are directly interpolated into HTML attribute context without being passed through esc_attr() or any other escaping function. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Timeline

1. Jun 2, 2026, 7:48 AM UTCCVE published
2. Jun 2, 2026, 10:38 AM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Jun 2, 2026, 10:47 AM UTCRecord last updated

Affected versions

• jhdscript ZeM STL

  through 1.0

References 9