WordPress security changelog
MEDIUM CVE-2026-4335 Deferred

ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF: Cross-site scripting

ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF is affected by cross-site scripting. Exploitation requires at least author-level access. Injected script can execute in the affected site's origin when the vulnerable output is viewed. The published affected range is <= 6.4.3.

CVE / CNA score 5.4 CVSS 3.1 · security@wordfence.com
NVD score Pending NVD has not published its own CVSS assessment.
Component
ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF
Plugin slug
shortpixel-image-optimiser
Affected
<= 6.4.3
Safe version
> 6.4.3
Published
Mar 26, 2026
Weakness
CWE-79 — Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

This CVE was published Mar 26, 2026 and is one of 4 known issues for this plugin.

What to do

Update, patch or deactivate.

Update ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF to a release after 6.4.3, or disable and remove it until a fixed version is available.

A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.

Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.

Source record

Technical 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.

CVE / CNA vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

References

Primary and upstream sources