ShortPixel Image Optimizer <= 6.4.3 — Authenticated (Author+) Stored Cross-Site Scripting via Attachment Title
CVE-2026-4335Published · Updated Action summary
Affected: ≤6.4.3Update to 6.4.4 or newer
All remediation steps- Severity
- Medium5.4
- CVSS
- 5.4CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:NWhat does this vector mean?
AV:NAttack vector- Network
AC:LAttack complexity- Low
PR:LPrivileges required- Low
UI:RUser interaction- Required
S:CScope- Changed
C:LConfidentiality- Low
I:LIntegrity- Low
A:NAvailability- None
- Weakness
- CWE-79 Cross-Site Scripting
- Required access
- Unknown
- Exploit prediction (EPSS)
- No score
- CISA KEV
- Not listed
On this page8
Am I affected?
ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF shortpixel-image-optimiser
- Affected≤ 6.4.3
- Patched in6.4.4
Update to 6.4.4 or newer.
You are affected if you run ≤ 6.4.3. Version 6.4.4 and later are not affected by this issue.
- Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF.
- No admin access? Run a passive check of your site. It reads public files only.
What to do
- Update to version 6.4.4, or a newer patched version
- Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
- Watch ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF to get an email when the next vulnerability is published.
Advisory
Source description from Wordfence Intelligence, credited to daroo.
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.
Exploits & references
Proof-of-concept & detection
No public proof-of-concept or detection template is known for this vulnerability.
Advisories & patches
- Advisorywordfence.com
Related CVEs
More in ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF
All 11| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| Medium6.4 | Authenticated (Contributor+) Stored Cross-Site Scripting ≤6.5.6Update to 6.6.0 | CVE-2026-103070 | |
| High7.5 | Authenticated (Subscriber+) PHP Object Injection ≤6.5.5Update to 6.5.6 | CVE-2026-97246 | |
| High8.8 | Authenticated (Author+) PHP Object Injection via Nested JSON Post Content ≤6.5.5Update to 6.5.6 | CVE-2026-17086 | |
| High7.5 | Authenticated (Author+) PHP Object Injection ≤6.4.3Update to 6.4.4 | CVE-2026-39471 | |
| Medium4.9 | Authenticated (Editor+) Arbitrary File Read via 'loadFile' Parameter ≤6.4.2Update to 6.4.3 | CVE-2026-1246 |
- Medium6.4Authenticated (Contributor+) Stored Cross-Site Scripting
≤6.5.6Update to 6.6.0
- High7.5Authenticated (Subscriber+) PHP Object Injection
≤6.5.5Update to 6.5.6
- High8.8Authenticated (Author+) PHP Object Injection via Nested JSON Post Content
≤6.5.5Update to 6.5.6
- High7.5Authenticated (Author+) PHP Object Injection
≤6.4.3Update to 6.4.4
- Medium4.9Authenticated (Editor+) Arbitrary File Read via 'loadFile' Parameter
≤6.4.2Update to 6.4.3
Same weakness (Cross-Site Scripting)
All Cross-Site Scripting| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| High7.2 | Unauthenticated Stored Cross-Site Scripting via Comment User-Agent Header | CVE-2026-120688 | |
| Critical9.8 | Unauthenticated Arbitrary File Upload via File Upload via Public Form Submission | CVE-2026-125055 | |
| Critical9.8 | Unauthenticated PHP Object Injection to Remote Code Execution via 'form' Parameter | CVE-2026-119077 | |
| Medium5.3 | Unauthenticated Sensitive Information Exposure in 'search' Parameter | CVE-2026-121518 |
- High7.2Unauthenticated Stored Cross-Site Scripting via Comment User-Agent Header
EZ SQL Reports Shortcode Widget and DB Backup
≤5.25.25Update to 5.26.45
- Critical9.8Unauthenticated Arbitrary File Upload via File Upload via Public Form Submission
Chatterbug Forms – Fast, Flexible WordPress Form Builder
≤1.0.2Update to 1.1
- Critical9.8Unauthenticated PHP Object Injection to Remote Code Execution via 'form' Parameter
ELEX WordPress HelpDesk & Customer Ticketing System
≤3.3.9Update to 3.4.0
- Medium5.3Unauthenticated Sensitive Information Exposure in 'search' Parameter
Customer Reviews for WooCommerce
≤5.127.0Update to 5.128.0
Timeline
CVE published
Severity medium, CVSS 5.4
Record last updated
Sources & licenses
Wordfence record- Vulnerability data
- Wordfence Intelligence. Copyright 2012-2026 Defiant Inc. Licensed under the CC BY-SA 4.0.
- CVE® identifiers
- Copyright 1999-2026 The MITRE Corporation. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
- CVSS / CWE
- National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.
- VulnCrest content
- Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.