XSS in Ewww Image Optimizer

CVE-2026-91011

The EWWW Image Optimizer WordPress plugin before 8.7.7 does not properly escape image attribute values when it rewrites page output, allowing authenticated users with author-level access and above to inject arbitrary JavaScript that is stored in published content and executes in the browser of any user who later views the affected page.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (37.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 37.4% 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-2026-91011: held from 0.004 to 0.004.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

  • Ewww Image Optimizer

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-91011?
CVE-2026-91011 is a medium-severity vulnerability in Ewww Image Optimizer, classified under Cross-site Scripting. CVSS score: 6.8/10. Published 2026-09-17.
How severe is CVE-2026-91011?
Medium severity. CVSS v3 base score is 6.8 out of 10.