a3 Lazy Load <= 2.7.6 - Authenticated (Contributor+) Stored Cross-Site Scripting via Video Element
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | a3 Lazy Load | <= 2.7.6 | 2.7.7 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N- Weakness (CWE)
CWE-79- Platform
- WordPress
- Package
a3 Lazy Load- Disclosed
- 27.05.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
Wordfence Intelligence - 5246efbb-93cc-4951-900e-d13d08840f03 - Wordfence Intelligence
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Copyright 2012-2026 Defiant Inc.
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Vulnerability history: a3 Lazy Load
All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 4
- First → latest
- 05.2022 05.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 2
- Medium 2
Disclosures per year
- 2022: 2
- 2023: 0
- 2024: 0
- 2025: 1
- 2026: 1
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a3 Lazy Load <= 2.7.6 - Authenticated (Contributor+) Stored Cross-Site Scripting via Video Element this entry
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