PT-2026-43531 · Gapgag55 · Auto Thumbnails

Published 2026-05-27 · Updated 2026-05-27 · CVE-2026-8899

Mitre

CVSS v3.1

6.4

Medium

Base vector

AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

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 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.

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2026-8899

Affected Products

Auto Thumbnails

References · 4

• https://nvd.nist.gov/vuln/detail/CVE-2026-8899 · Security Note
• https://plugins.trac.wordpress.org/browser/automatic-thumbnail/tags/1.0/index.php#L34 · Note
• https://plugins.trac.wordpress.org/browser/automatic-thumbnail/tags/1.0/index.php#L13 · Note
• https://wordfence.com/threat-intel/vulnerabilities/id/f0cc349a-96f9-4b11-a0b4-28bc4ccc022c?source=cve · Note