CVE-2026-18547

Ultimate Member <= 2.12.1 - Authenticated (Subscriber+) Stored Cross-Site Scripting via Textarea Profile Field with HTML Support (DOM Gadget via id Attribute)

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.

We have discovered 40,842 live websites that are affected by CVE-2026-18547.

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Affected Software

Product  Ultimate Member
Category Wordpress Plugins
Vulnerable Domains40,842 live websites (100% of Ultimate Member install base)
Vulnerable Versions
  • from 0 through 2.12.1
Vulnerable Versions Count109 versions ( 100% of all versions)


Common Weakness Enumeration

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')



Details

  • Published - Aug 25, 2026
  • Updated - Aug 25, 2026

Credits

  • tiborisaak (finder)

Website Distribution by Country

Number of websites using CVE-2026-18547
United States11,075 websites


Germany6,033 websites
France3,244 websites
GB1,915 websites
Italy1,788 websites
Spain1,666 websites
Netherlands1,260 websites
Canada978 websites
Switzerland859 websites
Japan635 websites

Website Distribution by TLD

Number of websites using CVE-2026-18547
.com13,875 websites
.org4,723 websites
.de3,886 websites
.fr1,560 websites
.it1,269 websites
.nl1,158 websites
.net952 websites
.co.uk846 websites
.es793 websites
.ch677 websites

Vulnerable Versions

Vulnerable versions are highlighted in red

Websites affected by CVE-2026-18547

Top websites that are affected by CVE-2026-18547. Please click on the "Contact us" link to get more information.
DomainCountryRankContacts
******.com United States**,***
***********.net United States**,***
****.org United States**,***
*****.com United States**,***
****.nu Netherlands**,***
*******.com United States**,***
******.de United States**,***
******.net United States**,***
*******.com GB**,***
**********.com United States**,***
See full domain list

FAQ

CVE-2026-18547 is Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in Ultimate Member
A total of 40,842 websites have been identified as vulnerable to CVE-2026-18547, based on global website indexing conducted by WebTechSurvey.
The Ultimate Member is affected by the CVE-2026-18547 vulnerability.
Ultimate Member versions up to and including 2.12.1 are vulnerable to CVE-2026-18547.

References