What the vulnerability does
01Description
The JSON API User plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'content' parameter of the post_comment API endpoint in versions up to, and including, 4.1.0 This is due to insufficient input sanitization in the post_comment() function, which passes the attacker-controlled comment_content value directly to wp_insert_comment() without applying any HTML sanitization, and additionally allows the caller to set comment_approved=1 to self-approve the comment and bypass moderation. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
Explanation of Vulnerability in Simple Terms
02Summary
JSON API User versions up to 4.1.0 contain a cross-site scripting (XSS) vulnerability that allows authenticated users to inject malicious scripts. The vulnerability has scope change, meaning injected code can affect other users or site functionality. An attacker with low-level account access can craft requests that execute JavaScript in victims' browsers, potentially stealing session tokens or performing actions on their behalf.
What an attacker can do
03Attacker Capabilities
Inject JavaScript code that runs in other users' browsers and affects site functionality.
Potential impact on your site
04Site Impact
Authenticated users can be compromised; attackers may steal sessions, modify content, or escalate privileges.
Conditions required to exploit
05Prerequisites
Attacker must have a low-privilege account on the site; no user interaction required.
Key dates
06Disclosure timeline
July 3, 2026
CVE published
