CVE-2026-39471

Stored XSS vulnerability in ShortPixel Image Optimizer (up to 6.5.6) due to improper input neutralization.

The ShortPixel Image Optimizer plugin through 6.5.5 contains a deserialization of untrusted data vulnerability allowing object injection. This may lead to unauthorized actions within the WordPress application context.

The ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 6.5.5 via deserialization of untrusted input. This makes it possible for authenticated attackers, with author-level access and above, to inject a PHP Object. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present.

The ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the 'shortpixel_ajaxRequest' AJAX action in all versions up to, and including, 6.3.4. This makes it possible for authenticated attackers, with Contributor-level access and above, to export and import site options.