CVE-2026-6427 | 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.

Published: 2026-05-28 Last update: 2026-05-28 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-6427 is rated Low Risk (29.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.21%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-6427

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.04% 0.21% +0.16%
2 2026-05-28 — 0.04% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-6427

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.1 2.7 [email protected]

Weakness enumeration for CVE-2026-6427

GitHub Security Advisory for CVE-2026-6427

GHSA-xgw3-j63x-rv92 · Severity: medium — The a3 Lazy Load plugin for WordPress is vulnerable to Stored Cross-Site Scripting in all...

Affected software / configurations for CVE-2026-6427

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-6427

URL Tags
https://plugins.trac.wordpress.org/browser/a3-lazy-load/trunk/admin/views/form-data.php#L11
https://plugins.trac.wordpress.org/browser/a3-lazy-load/trunk/classes/class-a3-lazy-load.php#L124
https://plugins.trac.wordpress.org/browser/a3-lazy-load/trunk/classes/class-a3-lazy-load.php#L136
https://plugins.trac.wordpress.org/browser/a3-lazy-load/trunk/classes/class-a3-lazy-load.php#L623
https://plugins.trac.wordpress.org/browser/a3-lazy-load/trunk/classes/class-a3-lazy-load.php#L643
https://plugins.trac.wordpress.org/browser/a3-lazy-load/trunk/classes/class-a3-lazy-load.php#L666
https://plugins.trac.wordpress.org/changeset?old_path=%2Fa3-lazy-load/tags/2.7.6&new_path=%2Fa3-lazy-load/tags/2.7.7
https://www.wordfence.com/threat-intel/vulnerabilities/id/5246efbb-93cc-4951-900e-d13d08840f03?source=cve
cvelogic Threat Intelligence