Deserialization in Shortpixel Image Optimizer – Optimize Images, Convert Webp & Avif

CVE-2026-17086

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.

Vulnerability class: Insecure Deserialization

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.013 (71.0th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 71st percentile — 71.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-17086: held from 0.009 to 0.013.

EPSS over last 30 days · oldest: 0.009 · newest: 0.013 · change: +0.004

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-17086?
CVE-2026-17086 is a high-severity vulnerability in Shortpixel Image Optimizer – Optimize Images, Convert Webp & Avif, classified under Deserialization of Untrusted Data. CVSS score: 8.8/10. Published 2026-09-18.
How severe is CVE-2026-17086?
High severity. CVSS v3 base score is 8.8 out of 10.