CVE-2026-63428

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.

Affected Software

VendorProductVersion RangeStatus
heyformheyform< 3.0.0-rc.9affected

Weaknesses

  • CWE-20: CWE-20: Improper Input Validation
  • CWE-915: CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: yes
    • Technical Impact: partial

Additional References

References