CVE-2026-18547: XSS (CVSS 6.4)

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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CVSS v3.1 Score

6.4

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.11%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://plugins.trac.wordpress.org/browser/ultimate-member/tags/2.11.4/assets/js/common.js#L51 https://plugins.trac.wordpress.org/browser/ultimate-member/tags/2.11.4/includes/class-functions.php#L580 https://plugins.trac.wordpress.org/browser/ultimate-member/tags/2.11.4/includes/core/class-form.php#L853 https://plugins.trac.wordpress.org/browser/ultimate-member/tags/2.12.1/assets/js/common.js#L51 https://plugins.trac.wordpress.org/browser/ultimate-member/tags/2.12.1/includes/class-functions.php#L580 https://plugins.trac.wordpress.org/browser/ultimate-member/tags/2.12.1/includes/core/class-form.php#L853 https://plugins.trac.wordpress.org/changeset?reponame=&old=3663931%40ultimate-member&new=3663931%40ultimate-member https://www.wordfence.com/threat-intel/vulnerabilities/id/a7961bcc-eae7-40e1-8838-9755c7655500?source=cve

Frequently Asked Questions

What is CVE-2026-18547? +

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. It has a CVSS v3.1 base score of 6.4 (MEDIUM).

How severe is CVE-2026-18547? +

CVE-2026-18547 has a CVSS v3.1 score of 6.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0021, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-18547? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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