cvedb.io
CVE-2026-63428
MEDIUM · CVSS 5.8
EPSS exploitation probability: 0%
Published 2026-07-20T16:17:06.680 · Last modified 2026-07-20T17:18:21.297

Summary

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.

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.