CVE-2026-12939
Received Received - Intake

Stored XSS in Newsletters Lite WordPress Plugin

Publication date: 2026-07-29

Last updated on: 2026-07-29

Assigner: Wordfence

Description
The Newsletters Lite plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'link' attribute of the post_thumbnail (and newsletters_post_thumbnail) shortcodes in versions up to and including 4.15. This is due to insufficient input sanitization and output escaping in the post_thumbnail() method in helpers/shortcode.php, which concatenates the user-controlled $link shortcode attribute directly into an href attribute without esc_url() or esc_attr(). 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.

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Meta Information

Published
2026-07-29
Last Modified
2026-07-29
Generated
2026-07-29
AI Q&A
2026-07-29
EPSS Evaluated
N/A
NVD
CVE-2026-12939
EUVD
EUVD-2026-50096

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
newsletter_lite newsletter_lite to 4.15 (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 Newsletters Lite WordPress plugin has a stored Cross-Site Scripting (XSS) vulnerability in versions up to 4.15. It allows authenticated attackers with contributor access or higher to inject malicious scripts via the 'link' attribute in the post_thumbnail shortcode. The vulnerability exists because user input is not properly sanitized or escaped before being included in the href attribute of the generated HTML.

Detection Guidance

Check for the Newsletters Lite plugin version 4.15 or lower. Inspect WordPress posts or pages for injected scripts in the post_thumbnail shortcode link attribute. Use WordPress admin panel to review plugin versions and content.

Impact Analysis

An attacker could inject scripts that steal user sessions, redirect to malicious sites, or perform actions on behalf of users. Visitors to affected pages may have their data compromised or be exposed to further attacks. The impact depends on the privileges of the injected script and the actions users can perform on the site.

Compliance Impact

This vulnerability could lead to unauthorized access to user data, violating GDPR's data protection requirements and HIPAA's safeguards for protected health information. If exploited, it may result in data breaches, triggering mandatory breach notifications and potential fines under these regulations.

Mitigation Strategies

Update the Newsletters Lite plugin to the latest version. Remove or sanitize any suspicious scripts in post_thumbnail shortcode attributes. Restrict contributor-level access to prevent unauthorized changes.

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