CVE-2026-18547
Received Received - Intake

Stored XSS in Ultimate Member WordPress Plugin via Profile Field

Publication date: 2026-08-25

Last updated on: 2026-08-25

Assigner: Wordfence

Description
The Ultimate Member – User Profile, Registration, Login, Member Directory, Content Restriction & Membership Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Textarea Profile Field with HTML Support (DOM Gadget via id Attribute) in all versions up to, and including, 2.12.1 due to insufficient input sanitization and output escaping. 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. This is possible because the wp_kses 'templates' allowlist permits the id attribute on div elements but does not neutralize unescaped quotes within its value; when pickadate.js concatenates the stored id value into an HTML string via jQuery .html() on profile page load, the smuggled onfocus and autofocus attribute syntax breaks out of attribute context and executes as JavaScript.

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Meta Information

Published
2026-08-25
Last Modified
2026-08-25
Generated
2026-08-25
AI Q&A
2026-08-25
EPSS Evaluated
N/A
NVD
CVE-2026-18547
EUVD
EUVD-2026-65460

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
ultimate_member ultimate_member to 2.12.1 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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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.

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Executive Summary

This is a Stored Cross-Site Scripting (XSS) vulnerability in the Ultimate Member WordPress plugin. It allows authenticated attackers with subscriber-level access or higher to inject malicious scripts into web pages. The issue occurs due to insufficient input sanitization and output escaping in the Textarea Profile Field with HTML Support feature. The plugin's wp_kses allowlist permits the id attribute on div elements but fails to neutralize unescaped quotes, enabling JavaScript execution when the id value is processed by pickadate.js and jQuery.

Detection Guidance

Check WordPress sites using Ultimate Member plugin versions up to 2.12.1. Look for unauthorized script injections in textarea profile fields. Inspect page source for suspicious id attributes containing onfocus or autofocus attributes. Use Wordfence scanner or similar tools to detect stored XSS patterns.

Impact Analysis

An attacker could inject malicious scripts that execute when users visit affected pages. This could lead to theft of cookies, session tokens, or other sensitive data. It may also allow attackers to perform actions on behalf of users, modify page content, or redirect users to malicious sites. The impact depends on user privileges and the nature of the injected scripts.

Compliance Impact

This vulnerability could lead to unauthorized access to user data, violating GDPR's data protection principles and HIPAA's security requirements for protected health information. It may result in data breaches, unauthorized data access, or loss of data integrity, all of which are compliance violations under these regulations.

Mitigation Strategies

Update Ultimate Member plugin to the latest version beyond 2.12.1 immediately. Disable subscriber-level access temporarily if possible. Implement strict input validation for profile fields. Use security plugins to block XSS payloads. Monitor for unusual script activity in user profiles.

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