formie's unauthenticated front-end submission editing can overwrite existing submissions
Date: 2026-05
Affected: composer/verbb/formie, composer/verbb/formie
Attack vector: auth-bypass
Category: vulnerability-disclosure
Severity: High
CVE: CVE-2026-47266
CWE: CWE-639

### Impact Unauthenticated users could modify existing submissions by posting a known or guessed submission ID to `formie/submissions/save-submission`. ### Patches [2.2.21](https://github.com/verbb/formie/releases/tag/2.2.21), [3.1.26](https://github.com/verbb/formie/releases/tag/3.1.26) ### Workarounds Block unauthenticated access to `actions/formie/submissions/save-submission`, or disable/customize front-end submission editing until patched. ### Credit formie extends many thanks to: - Florian (Cyber Security Engineer, arcade solutions ag) - Contact: [security@arcade.ch](mailto:security@arcade.ch)


Mitigations:

Architectural layers (MAESTRO):