CVE-2026-15446

EWWW Image Optimizer <= 8.7.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'data-script' Lazy Load Attribute in Post Content

2026-08-18 17:52
UKO

Strategic Overview

Status
Patched in 8.7.4
Affected Plugin
EWWW Image Optimizer
Affected Version
<= 8.7.3
CVSS
6.4Medium
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2026-15446
View all EWWW Image Optimizer vulnerabilities

At a glance

CVE-2026-15446 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the EWWW Image Optimizer WordPress plugin, affecting versions <= 8.7.3. It carries a CVSS score of 6.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Contributor level or above. The issue is fixed in version 8.7.4; sites on affected versions should update now. Disclosed August 2026, reported by UKO.

Vulnerability Overview

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.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

EWWW Image Optimizer <= 8.7.3 carries this weakness at data-script, and reaching it takes an account at Contributor level or above. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For EWWW Image Optimizer the fix is 8.7.4: builds <= 8.7.3 are affected, anything from 8.7.4 onward is not.

Remediation

Update to version 8.7.4, or a newer patched version

How does WordSec protect against this?

An attacker needs Contributor access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: EWWW Image Optimizer 8.7.4 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-15446https://www.wordfence.com/threat-intel/vulnerabilities/id/e8af1fdb-7fec-4bbe-937b-ee2e76cf5c5bhttps://nvd.nist.gov/vuln/detail/CVE-2026-15446

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C