Stored XSS in FooGallery WordPress Plugin

Publication date: 2026-06-13

Last updated on: 2026-06-15

Assigner: Wordfence

Description

The FooGallery plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'custom_attribute_key' shortcode parameter in versions up to, and including, 3.1.31 This is due to an incomplete JavaScript event handler blacklist in the foogallery_sanitize_javascript() function, which blocks only a subset of HTML event attributes (onmouseover, onmouseout, onpointerenter, onclick, onload, onchange, onerror) while permitting others such as 'onmouseenter', combined with the failure to escape the attribute key when building the gallery container HTML in foogallery_build_container_attributes_safe(). 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.

CVSS Scores

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Meta Information

Published

2026-06-13

Last Modified

2026-06-15

Generated

2026-07-03

AI Q&A

2026-06-13

EPSS Evaluated

2026-07-02

NVD

CVE-2026-9134

EUVD

EUVD-2026-36645

Affected Vendors & Products

Vendor	Product	Version / Range
foogallery	foogallery	to 3.1.31 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-79	The product 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.

Attack-Flow Graph

Executive Summary

The FooGallery plugin for WordPress has a Stored Cross-Site Scripting (XSS) vulnerability in versions up to and including 3.1.31. This vulnerability arises from an incomplete blacklist of JavaScript event handlers in the foogallery_sanitize_javascript() function, which blocks only some HTML event attributes but allows others like 'onmouseenter'. Additionally, the plugin fails to properly escape the 'custom_attribute_key' shortcode parameter when building gallery container HTML. As a result, authenticated users with contributor-level access or higher can inject malicious scripts that execute whenever a page containing the injected code is accessed.

Impact Analysis

This vulnerability allows attackers with contributor-level access or higher to inject arbitrary JavaScript into pages. When other users visit these pages, the malicious scripts execute in their browsers, potentially leading to theft of sensitive information, session hijacking, defacement, or further exploitation of the website. Since the attack requires authenticated access, it can be used to escalate privileges or compromise user trust.

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