CVE-2026-63429

HIGH 8.6

HeyForm has unauthenticated /api/upload endpoint that accepts arbitrary files with no auth/session/form context

CVSS Score

8.6

EPSS Score

0.0%

EPSS Percentile

0th

HeyForm is an open-source form builder. Prior to version 3.0.0-rc.9, `POST /api/upload` has no authentication guard, no global guard, no form-context validation, no `openToken` requirement, and no session cookie check. Any anonymous internet user can upload files (PDF, DOC/DOCX, XLS/XLSX, CSV, TXT, MP4, images, etc., up to 10 MB) and receive a permanent public URL on the HeyForm domain. The endpoint is used by both authenticated form creators and unauthenticated form submitters; because no form-context binding exists, every request to it is anonymously accepted. Version 3.0.0-rc.9 contains a patch for the issue.

CWE	CWE-306 CWE-434
Vendor	heyform
Product	heyform
Published	Jul 20, 2026
Last Updated	Jul 20, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

High

Availability

Low

Affected Versions

heyform / heyform

< 3.0.0-rc.9

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/heyform/heyform/security/advisories/GHSA-432x-54v2-p7p7 github.com: https://github.com/heyform/heyform/commit/092e255e9e02565de1b3c057f3dad849160952d2