CVE-2026-18100

MetForm <= 4.1.8 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'mf_form_id' Widget Setting

The MetForm – Contact Form, Survey, Quiz, & Custom Form Builder for Elementor plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'mf_form_id' Widget Setting in all versions up to, and including, 4.1.8 due to insufficient input sanitization and output escaping. 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. The payload bypasses Elementor's save-time wp_kses_post filter because it contains no HTML tags, and MetForm's own str_replace transformation of script tags into JavaScript template literal expressions provides an additional delivery path.

We have discovered 46,439 live websites that are affected by CVE-2026-18100.

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Affected Software

Product  Metform
Category Wordpress Plugins
Vulnerable Domains46,439 live websites (100% of Metform install base)
Vulnerable Versions
  • from 0 through 4.1.8
Vulnerable Versions Count91 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

  • Jonah Burgess (CryptoCat) (finder)

Website Distribution by Country

Number of websites using CVE-2026-18100
United States12,446 websites


Germany3,876 websites
Brazil3,018 websites
India2,671 websites
GB2,313 websites
France1,935 websites
Cyprus1,665 websites
Spain1,632 websites
Italy1,508 websites
Canada1,010 websites

Website Distribution by TLD

Number of websites using CVE-2026-18100
.com21,135 websites
.com.br2,815 websites
.org1,843 websites
.de1,774 websites
.co.uk1,159 websites
.it1,126 websites
.net927 websites
.nl899 websites
.fr845 websites
.pl741 websites

Vulnerable Versions

Vulnerable versions are highlighted in red

Websites affected by CVE-2026-18100

Top websites that are affected by CVE-2026-18100. Please click on the "Contact us" link to get more information.
DomainCountryRankContacts
********.***.br Brazil**,***
*************.de Germany**,***
**********.com United States**,***
********.net United States**,***
*******.org Cyprus**,***
***********.com United States**,***
********.com United States**,***
**************.net United States**,***
*****.io United States**,***
*****.com Bangladesh**,***
See full domain list

FAQ

CVE-2026-18100 is Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in Metform
A total of 46,439 websites have been identified as vulnerable to CVE-2026-18100, based on global website indexing conducted by WebTechSurvey.
The Metform is affected by the CVE-2026-18100 vulnerability.
Metform versions up to and including 4.1.8 are vulnerable to CVE-2026-18100.

References