ShortPixel Image Optimizer <= 6.5.5 - Authenticated (Author+) PHP Object Injection via Nested JSON Post Content
Published Sep 18, 2026 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
ShortPixel Image Optimizer <= 6.5.5 - Authenticated (Author+) PHP Object Injection via Nested JSON Post Content
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
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.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- MEDIUM
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
- www.wordfence.com ↗
- plugins.trac.wordpress.org ↗
- plugins.trac.wordpress.org ↗
- plugins.trac.wordpress.org ↗
- plugins.trac.wordpress.org ↗
- plugins.trac.wordpress.org ↗
- plugins.trac.wordpress.org ↗
- plugins.trac.wordpress.org ↗
- plugins.trac.wordpress.org ↗
- plugins.trac.wordpress.org ↗
- plugins.trac.wordpress.org ↗
- plugins.trac.wordpress.org ↗
Record history
Published Sep 18, 2026 · Last refreshed Nov 3, 2026