Vulnerability · Published Mar 26, 2026 · Assigned by Wordfence
CVE-2026-4335ShortPixel Image Optimizer <= 6.4.3 - Authenticated (Author+) Stored Cross-Site Scripting via Attachment Title
Medium 5.4
In plain English
A medium-severity cross-site scripting in ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF from shortpixel. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities).
Official description
The ShortPixel Image Optimizer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the attachment post_title in all versions up to, and including, 6.4.3. This is due to insufficient output escaping in the getEditorPopup() function and its corresponding media-popup.php template. Specifically, the attachment's post_title is retrieved from the database via get_post() in AjaxController.php (line 435) and passed directly to the view template (line 449), where it is rendered into an HTML input element's value attribute without esc_attr() escaping (media-popup.php line 139). Since WordPress allows Authors to set arbitrary attachment titles (including double-quote characters) via the REST API, a malicious author can craft an attachment title that breaks out of the HTML attribute and injects arbitrary JavaScript event handlers. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts that execute whenever a higher-privileged user (such as an administrator) opens the ShortPixel AI editor popup (Background Removal or Image Upscale) for the poisoned attachment.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| shortpixel | ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF | 0 – through 6.4.3 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
References
- https://www.wordfence.com/threat-intel/vulnerabilities/id/a156234f-2644-4d17-aaa5-4f088cf48f73?source=cve
- https://plugins.trac.wordpress.org/browser/shortpixel-image-optimiser/trunk/class/view/snippets/media-popup.php#L139
- https://plugins.trac.wordpress.org/browser/shortpixel-image-optimiser/tags/6.4.3/class/view/snippets/media-popup.php#L139
- https://plugins.trac.wordpress.org/browser/shortpixel-image-optimiser/trunk/class/Controller/AjaxController.php#L449
- https://plugins.trac.wordpress.org/browser/shortpixel-image-optimiser/tags/6.4.3/class/Controller/AjaxController.php#L449
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3490270%40shortpixel-image-optimiser&new=3490270%40shortpixel-image-optimiser&sfp_email=&sfph_mail=