CVE-2026-52889
CriticalCVSS 9.8Summary
Formie, a Craft CMS plugin for creating forms, before version 3.1.27 passes request-derived Hidden field defaults (e.g., User Agent, URL, query parameters) to Craft's Twig rendering layer. An unauthenticated attacker can place Twig syntax in these values, leading to server-side template evaluation (SSTI), potentially resulting in information disclosure, application state modification, or remote code execution.
Risk Assessment
An attacker can exploit the vulnerability to obtain sensitive information, modify application state, or achieve remote code execution, potentially leading to full site compromise.
Recommendation
Update Formie to version 3.1.27 or later. Review public forms for Hidden fields and restrict passing request data to Twig.
Original NVD description (English source)
Formie is a Craft CMS plugin for creating forms. Prior to 3.1.27, Formie can pass request-derived Hidden field defaults such as HTTP User Agent, Referer URL, Current URL, Current URL without Query String, Query Parameter, and Cookie Value to Craft's Twig rendering layer during front-end form rendering. An unauthenticated attacker can place Twig syntax in one of these request-controlled inputs when a public form contains an affected Hidden field. Hidden::getFrontEndInputOptions() then assigns the value to defaultValue and calls renderString, causing server-side template evaluation rather than treating the request data as a plain string. Depending on the Craft site configuration and available Twig capabilities, exploitation can disclose sensitive information, modify application state, or achieve remote code execution. This issue is fixed in version 3.1.27.