CVE-2026-4335 ShortPixel Image Optimizer <= 6.4.3 - Authenticated (Author+) Stored Cross-Site Scripting via Attachment Title
Authenticated authors can inject scripts via attachment titles, executing code in admin sessions when opening the image editor popup.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-4335?
CVE-2026-4335 is a medium-severity cross-site scripting vulnerability in ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF, published on 26 Mar 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-4335?
How do I fix CVE-2026-4335?
No fix has been published for CVE-2026-4335 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-4335 being exploited?
There is no known exploitation of CVE-2026-4335 in the wild and no public exploit code.
Sources
Also known as GHSA-g8cg-xh22-8v5v.