CVE-2026-63428
HeyForm: completeSubmission persists submitter-supplied hidden fields verbatim without validating against the form's declared hidden-field set
Description
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.
INFO
Published Date :
July 20, 2026, 4:17 p.m.
Last Modified :
July 20, 2026, 5:18 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-63428
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update HeyForm to version 3.0.0-rc.9 or later.
- Validate user-supplied hidden fields against the form schema.
- Sanitize all data before storing and forwarding submissions.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-63428.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-63428 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-63428
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-63428 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-63428 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 20, 2026
Action Type Old Value New Value Added Reference https://github.com/heyform/heyform/security/advisories/GHSA-r7vg-xh87-v4w3 Added SSVC {'id': 'CVE-2026-63428', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-20T16:11:40.127768Z'} -
New CVE Received by [email protected]
Jul. 20, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'heyform', 'product': 'heyform', 'versions': [{'status': 'affected', 'version': '< 3.0.0-rc.9'}]}] Added Description 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N Added CWE CWE-20 Added CWE CWE-915 Added Reference https://github.com/heyform/heyform/commit/092e255e9e02565de1b3c057f3dad849160952d2 Added Reference https://github.com/heyform/heyform/security/advisories/GHSA-r7vg-xh87-v4w3