CVE-2026-63428

Not enough EPSS history yet.

HeyForm is an open-source form builder. Prior to version 3.0.0-rc.9, `completeSubmission` accepts a `hiddenFields: [{id, name, value}]` array from the submitter and stores it verbatim in `submission.hiddenFields`, without validating the supplied `id`/`name` against the form's declared `form.hiddenFields` schema. An anonymous form submitter can therefore inject arbitrary key/value pairs (including XSS payloads, fake authorization metadata, integration-relevant values) into the stored submission. These fields are subsequently forwarded as-is to every webhook integration registered on the form. Version 3.0.0-rc.9 contains a patch for the issue.

• github.comhttps://github.com/heyform/heyform/commit/092e255e9e02565de1b3c057f3dad849160952d2
• github.comhttps://github.com/heyform/heyform/security/advisories/GHSA-r7vg-xh87-v4w3
• github.comhttps://github.com/heyform/heyform/security/advisories/GHSA-r7vg-xh87-v4w3