What the vulnerability does
01Description
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.
Explanation of Vulnerability in Simple Terms
02Summary
ZeM STL versions 1.0 and earlier contain a cross-site scripting (XSS) vulnerability that allows authenticated users to inject malicious scripts affecting other users and the site. The vulnerability has scope impact, meaning injected code can affect areas beyond the vulnerable component. Low-privileged accounts can exploit this without user interaction.
What an attacker can do
03Attacker Capabilities
Inject malicious scripts that execute in other users' browsers and affect site functionality.
Potential impact on your site
04Site Impact
Authenticated users can deface pages, steal session data, or redirect visitors to malicious sites.
Conditions required to exploit
05Prerequisites
Attacker must have a low-privileged account; no user interaction required from victims.
Key dates
06Disclosure timeline
June 2, 2026
CVE published
June 2, 2026
Record updated
