EWWW Image Optimizer <= 8.7.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'data-script' Lazy Load Attribute in Post Content
Published Aug 19, 2026 · Updated Oct 23, 2026
Original summary
Normalized public record · Updated Oct 23, 2026
EWWW Image Optimizer <= 8.7.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'data-script' Lazy Load Attribute in Post Content
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
The EWWW Image Optimizer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'data-script' Lazy Load Attribute in Post Content in all versions up to, and including, 8.7.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The exploit is achieved by embedding a crafted img element with class='lazyload' and a data-script attribute pointing to an attacker-controlled URL in post content, which the plugin's bundled lazysizes ls.unveilhooks addon then uses to dynamically create and insert a script element into the DOM at page view time.
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
- LOW
- 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 ↗
- Patch commit ↗
Record history
Published Aug 19, 2026 · Last refreshed Oct 23, 2026