CVE-2026-4335

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.

Gravité et risque d'exploitation

CVE-2026-4335 obtient un score CVSS de 5.4/10, soit une gravité moyenne. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.31 %, ce qui la place devant 22.8 % des CVE référencées.

Que faire ?

• Vérifiez si ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF (versions 0, <=6.4.3) est présent sur votre parc.
• Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
• À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
• Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

• 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=