What the vulnerability does
01Description
The a3 Lazy Load plugin for WordPress is vulnerable to Stored Cross-Site Scripting in all versions up to, and including, 2.7.6 This is due to a regex bug in the _filter_videos() method that breaks HTML attribute quoting when processing crafted <video> elements, combined with unescaped output in the admin/views/form-data.php template. An authenticated attacker with Contributor-level access can insert a crafted <video> tag whose src attribute contains an embedded class=" substring that tricks the plugin's class-replacement regex into consuming an attribute-value closing quote. This shifts the HTML5 parser's quote boundary, promoting attacker-controlled text from inside a quoted attribute value into standalone event-handler attributes (autofocus, onfocus). The injected script executes in the browser of any user (including administrators) who views the post.
Explanation of Vulnerability in Simple Terms
02Summary
a3 Lazy Load versions 2.7.6 and earlier contain a cross-site scripting (XSS) vulnerability that allows authenticated users to inject malicious scripts. The vulnerability has a changed scope, meaning the impact can extend beyond the vulnerable component itself. Site administrators should update to a version newer than 2.7.6 to remediate this issue.
What an attacker can do
03Attacker Capabilities
Inject and execute malicious JavaScript in the site, affecting other users and potentially the site itself.
Potential impact on your site
04Site Impact
Authenticated attackers can inject scripts that compromise other users' sessions, steal data, or deface site content.
Conditions required to exploit
05Prerequisites
Attacker must have a low-privilege user account (e.g., subscriber or contributor role) on the site.
Key dates
06Disclosure timeline
May 28, 2026
CVE published
May 28, 2026
Record updated
