CVE-2026-4335 json
ShortPixel Image Optimizer <= 6.4.3 - Authenticated (Author+) Stored Cross-Site Scripting via Attachment Title
published 7mo ago modified 4mo ago also EUVD-2026-16087
- cvss
- 5.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 7%
- public exploits
- 0
- none known
Summary
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.
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 7mo ago
Exploit prediction
0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
Affected products
- shortpixel ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/a156234f-2644-4d17-aaa5-4f088cf48f73?source=cve
- plugins.trac.wordpress.org /browser/shortpixel-image-optimiser/trunk/class/view/snippets/media-popup.php#L139
- plugins.trac.wordpress.org /browser/shortpixel-image-optimiser/tags/6.4.3/class/view/snippets/media-popup.php#L139
- plugins.trac.wordpress.org /browser/shortpixel-image-optimiser/trunk/class/Controller/AjaxController.php#L449
- plugins.trac.wordpress.org /browser/shortpixel-image-optimiser/tags/6.4.3/class/Controller/AjaxController.php#L449
- plugins.trac.wordpress.org /changeset?sfp_email=&sfph_mail=&reponame=&old=3490270%40shortpixel-image-optimiser&new=3490270%40shortpixel-i
Sources
- CVE List CVE-2026-4335
- NVD CVE-2026-4335
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.