CVE-2026-8899
Received Received - Intake
Stored XSS in Auto Thumbnail WordPress Plugin

Publication date: 2026-05-27

Last updated on: 2026-05-27

Assigner: Wordfence

Description
The Auto Thumbnail plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'thumbnails' shortcode in all versions up to, and including, 1.0. This is due to insufficient input sanitization and output escaping on the shortcode's 'width' and 'height' attributes in the athn_thumbnails() function, which are concatenated directly into an HTML <img> tag. 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
2026-05-27
Last Modified
2026-05-27
Generated
2026-05-27
AI Q&A
2026-05-27
EPSS Evaluated
N/A
NVD
EUVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
wordfence auto_thumbnail to 1.0 (inc)
Helpful Resources
Exploitability
CWE
CWE Icon
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.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

The Auto Thumbnail plugin for WordPress has a Stored Cross-Site Scripting (XSS) vulnerability in all versions up to and including 1.0. This vulnerability arises because the plugin does not properly sanitize or escape input for the 'width' and 'height' attributes in the 'thumbnails' shortcode. These attributes are directly inserted into an HTML <img> tag, allowing authenticated users with contributor-level access or higher to inject malicious scripts. These scripts then execute whenever any user views the affected page.


How can this vulnerability impact me? :

This vulnerability can allow attackers with contributor-level access to inject arbitrary web scripts into pages. When other users access these pages, the malicious scripts execute in their browsers. This can lead to theft of user credentials, session hijacking, defacement of the website, or distribution of malware, compromising both site integrity and user security.


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