XSS in Optimole – Optimize Images | Convert Webp & Avif Cdn Lazy Load Image Optimization

CVE-2026-120739

The Optimole – Optimize Images | Convert WebP & AVIF | CDN & Lazy Load | Image Optimization plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 's (missing_srcsets[*][*].s)' parameter in all versions up to, and including, 4.2.18 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The HMAC signature required to pass the REST endpoint's authorization check is published in plaintext to unauthenticated visitors inside the inline optimoleDataOptimizer JavaScript object on any page with an incomplete profile, making the effective authentication barrier nonexistent.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-120739?
CVE-2026-120739 is a high-severity vulnerability in Optimole – Optimize Images | Convert Webp & Avif Cdn Lazy Load Image Optimization, classified under Cross-site Scripting. CVSS score: 7.2/10. Published 2026-11-07.
How severe is CVE-2026-120739?
High severity. CVSS v3 base score is 7.2 out of 10.