WPComplete (2.9.9.0) Stored XSS via empty shortcode attribute
CVE-2026-77820 Published on September 19, 2026
WPComplete <= 2.9.9.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'empty' Shortcode Attribute
The WPComplete plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'empty' Shortcode Attribute in all versions up to, and including, 2.9.9.0 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. This requires the premium version of the software in order to exploit. Please note this only affects the pro version.
Timeline
Vendor Notified
Disclosed 28 days later.
Weakness Type
What is a XSS Vulnerability?
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CVE-2026-77820 has been classified to as a XSS vulnerability or weakness.
Affected Versions
stellarwp WPComplete:- Before and including 2.9.9.0 is affected.