CVE-2026-8899
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.
Affected WordPress components
-
automatic-thumbnail Plugin · automatic-thumbnailUp to and including 1.0View on WordPress.org
A confirmed match is backed by the plugin or theme slug. A possible match is based on the product name only and should be verified.
Affected products and versions
- gapgag55 Auto Thumbnails — Up to and including 1.0
References
- plugins.trac.wordpress.org https://plugins.trac.wordpress.org/browser/automatic-thumbnail/tags/1.0/index.php#L13
- plugins.trac.wordpress.org https://plugins.trac.wordpress.org/browser/automatic-thumbnail/tags/1.0/index.php#L34
- www.wordfence.com https://www.wordfence.com/threat-intel/vulnerabilities/id/f0cc349a-96f9-4b11-a0b4-28bc4ccc022c?source=cve
- nvd.nist.gov Official NVD record