ShortPixel Image Optimizer <= 6.5.5 — Authenticated (Author+) PHP Object Injection via Nested JSON Post Content
CVE-2026-17086Published · Updated Action summary
Affected: ≤6.5.5Update to 6.5.6 or newer
All remediation steps- Severity
- High8.8
- CVSS
- 8.8CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HWhat does this vector mean?
AV:NAttack vector- Network
AC:LAttack complexity- Low
PR:LPrivileges required- Low
UI:NUser interaction- None
S:UScope- Unchanged
C:HConfidentiality- High
I:HIntegrity- High
A:HAvailability- High
- Weakness
- CWE-502 PHP Object Injection
- Required access
- Unknown
- Exploit prediction (EPSS)
- 1.3% chance in 30 days71th percentile
- CISA KEV
- Not listed
On this page8
Am I affected?
ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF shortpixel-image-optimiser
- Affected≤ 6.5.5
- Patched in6.5.6
Update to 6.5.6 or newer.
You are affected if you run ≤ 6.5.5. Version 6.5.6 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 6.5.6, 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 Josh Bolding.
The ShortPixel Image Optimizer – Optimize Images, Convert WebP & AVIF plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 6.5.5 via deserialization of untrusted input . This makes it possible for authenticated attackers, with author-level access and above, to inject a PHP Object. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present.
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 | |
| High7.5 | Authenticated (Author+) PHP Object Injection ≤6.4.3Update to 6.4.4 | CVE-2026-39471 | |
| Medium5.4 | Authenticated (Author+) Stored Cross-Site Scripting via Attachment Title ≤6.4.3Update to 6.4.4 | CVE-2026-4335 | |
| 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
- High7.5Authenticated (Author+) PHP Object Injection
≤6.4.3Update to 6.4.4
- Medium5.4Authenticated (Author+) Stored Cross-Site Scripting via Attachment Title
≤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 (PHP Object Injection)
All PHP Object Injection| 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 high, CVSS 8.8
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.
- EPSS
- Exploit Prediction Scoring System by FIRST.org.
- VulnCrest content
- Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.