Paper/Archive/CVE-2026-52889

CVE-2026-52889

verbb formie — Formie: Server-Side Template Injection in Formie Hidden field defaults

Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
formie< 3.1.27–CNA

Scores by source

GitHub_M (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refgithub.com/verbb/formie/security/advisories/GHSA-565m-g33j-jq96refgithub.com/verbb/formie/commit/d3b9d15290405e484e3b5c91c5d8fab93047f9b2refgithub.com/verbb/formie/releases/tag/3.1.27