Description
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.
Published: 2026-08-19
Score: 9.8 Critical
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories
Source ID Title
Github GHSA Github GHSA GHSA-565m-g33j-jq96 Formie Hidden field defaults vulnerable to Server-Side Template Injection
History

Wed, 19 Aug 2026 17:45:00 +0000

Type Values Removed Values Added
First Time appeared Verbb
Verbb formie
Vendors & Products Verbb
Verbb formie

Wed, 19 Aug 2026 15:15:00 +0000

Type Values Removed Values Added
Description 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.
Title Formie: Server-Side Template Injection in Formie Hidden field defaults
Weaknesses CWE-1336
References
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-19T18:05:26.381Z

Reserved: 2026-06-08T21:44:27.365Z

Link: CVE-2026-52889

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-19T15:17:09.957

Modified: 2026-08-19T18:16:43.520

Link: CVE-2026-52889

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-19T18:00:05Z

Weaknesses