CVE-2026-125409
Deferred Deferred - Pending Action

Stored XSS in Passster WordPress Plugin

Publication date: 2026-11-13

Last updated on: 2026-11-13

Assigner: Wordfence

Description
The Passster – Password Protect Pages and Content plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'metavalue (metakeyinput=passster_id | passster_headline)' parameter in all versions up to, and including, 4.3.21 due to insufficient input sanitization and output escaping. 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. A Contributor can break out of the shortcode attribute context by embedding a ] character in the passster_id or passster_headline meta value to prematurely close the opening shortcode tag, then append a [/passster] closing tag so that the trailing HTML payload is emitted verbatim by do_shortcode() — bypassing the per-attribute escaping present inside render_shortcode() — and the script will also execute in an editor's or administrator's browser when they preview the Contributor's pending post, since filter_the_content() has no edit-permission capability gate.

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Meta Information

Published
2026-11-13
Last Modified
2026-11-13
Generated
2026-11-13
AI Q&A
2026-11-13
EPSS Evaluated
N/A
NVD
CVE-2026-125409
EUVD
EUVD-2026-124982

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
wpchill Passster – Password Protect Pages and Content From 0 (inc) to 4.3.21 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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Executive Summary

The Passster plugin for WordPress has a stored cross-site scripting vulnerability due to insufficient input sanitization and output escaping in the 'metavalue' parameter. Authenticated attackers with contributor-level access or higher can inject malicious scripts into pages. The vulnerability allows bypassing shortcode attribute escaping by using a ] character to close the shortcode tag prematurely, enabling script execution when users access the page or when administrators preview posts.

Detection Guidance

Check for the Passster plugin version 4.3.21 or lower. Inspect WordPress pages for unusual meta values in passster_id or passster_headline parameters. Review user roles with contributor access or higher for suspicious activity.

Impact Analysis

This vulnerability allows attackers to inject malicious scripts into WordPress pages. If you are a site administrator or editor, these scripts could execute in your browser when previewing posts or accessing infected pages. The impact includes potential theft of session cookies, unauthorized actions on your behalf, or defacement of your website. Users visiting compromised pages may also have their data exposed or be redirected to malicious sites.

Compliance Impact

This vulnerability could lead to unauthorized access to user data, which may violate GDPR's data protection requirements or HIPAA's safeguards for protected health information. If exploited, it could result in data breaches, triggering compliance violations, legal penalties, and reputational damage for organizations handling sensitive user data.

Mitigation Strategies

Update the Passster plugin to the latest version. Remove or sanitize any injected scripts in meta values. Restrict contributor-level access to trusted users only.

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