Vulnerability · Published Aug 19, 2026 · Assigned by Wordfence
CVE-2026-15446EWWW Image Optimizer <= 8.7.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'data-script' Lazy Load Attribute in Post Content
Medium 6.4
In plain English
A medium-severity cross-site scripting in EWWW Image Optimizer from nosilver4u. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities).
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| nosilver4u | EWWW Image Optimizer | 0 – through 8.7.3 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
References
- https://www.wordfence.com/threat-intel/vulnerabilities/id/e8af1fdb-7fec-4bbe-937b-ee2e76cf5c5b?source=cve
- https://plugins.trac.wordpress.org/browser/ewww-image-optimizer/tags/8.7.3/includes/ls.unveilhooks.js#L116
- https://plugins.trac.wordpress.org/browser/ewww-image-optimizer/tags/8.7.3/includes/ls.unveilhooks.js#L178
- https://plugins.trac.wordpress.org/browser/ewww-image-optimizer/tags/8.7.3/classes/class-lazy-load.php#L1679
- https://plugins.trac.wordpress.org/browser/ewww-image-optimizer/tags/8.7.3/classes/class-lazy-load.php#L496
- https://plugins.trac.wordpress.org/browser/ewww-image-optimizer/tags/8.6.0/includes/ls.unveilhooks.js#L116
- https://plugins.trac.wordpress.org/browser/ewww-image-optimizer/tags/8.6.0/includes/ls.unveilhooks.js#L178
- https://plugins.trac.wordpress.org/browser/ewww-image-optimizer/tags/8.6.0/classes/class-lazy-load.php#L1679
- https://plugins.trac.wordpress.org/browser/ewww-image-optimizer/tags/8.6.0/classes/class-lazy-load.php#L496
- https://github.com/nosilver4u/ewww-image-optimizer/commit/4488aafaee9212db370a5ed2dcb9bad7912b897d