Reported vulnerability

ShortPixel Image Optimizer <= 6.4.3 - Authenticated (Author+) Stored Cross-Site Scripting via Attachment Title

Q: Which versions of ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF are affected?

Wordfence lists these affected versions: Start version unspecified, through 6.4.3. Use the version checker above to compare your installed release with this report.

Q: Is a fix available for ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF?

Wordfence reports a fix for this issue in ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF. It lists these fixed versions: 6.4.4. Back up your website and test the recommended update before applying it to your live site.

Q: Where can I find my installed plugin version?

In WordPress, open Plugins > Installed Plugins and find the version shown beneath the plugin name.

Published 25 Mar 2026

Updated 26 Mar 2026

CVE-2026-4335

Compare your installed software with the affected versions below. Follow the source’s remediation guidance and test an available update after taking a backup. A database entry describes a reported issue; it does not establish whether a particular website has been compromised.

Does this affect my version?

Check your installed version against this advisory. This compares the report’s version ranges and does not scan your website.

Wordfence advisory

medium · CVSS 5.4

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.

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

ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF

Software: plugin · shortpixel-image-optimiser
Affected versions: Start version unspecified, through 6.4.3
Fix availability: Fix available
Fixed versions: 6.4.4

Recommended action

Update to version 6.4.4, or a newer patched version

Further references (1)

wordfence.com/threat-intel/vulnerabilities/id/a156234f-2644-4d17-aaa5-4f088cf48f73?source=api-prod

Data sources and licences

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CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE®). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.

Read licence terms

Source: Wordfence

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Questions about this vulnerability

Which versions of ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF are affected?

Wordfence lists these affected versions: Start version unspecified, through 6.4.3. Use the version checker above to compare your installed release with this report.

Is a fix available for ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF?

Wordfence reports a fix for this issue in ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF. It lists these fixed versions: 6.4.4. Back up your website and test the recommended update before applying it to your live site.

Where can I find my installed plugin version?

In WordPress, open Plugins > Installed Plugins and find the version shown beneath the plugin name.

Does an affected version mean my website has been hacked?

An affected version means the installed release matches a vulnerability described in this report. It does not show whether anyone has exploited it on your website. The checker compares version numbers with stored reports; it does not inspect your website.

These reports cover at least one of the same plugins, themes or WordPress core. Check each report’s affected versions separately.

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