CVE-2026-63429CWE-306CWE-434

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

High · published July 20, 2026

CVSS v3.1
8.6
EPSS
1%
Percentile
42.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.6 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
CVSS v4.0
Not supplied
EPSS
0.00507 · 42.3th percentile
Weaknesses
CWE-306 · Missing Authentication for Critical Function; CWE-434 · Unrestricted Upload of File with Dangerous Type
Published
2026-07-20T15:54Z
EPSS history
Timeline
  • 20 JUL 15:54Z
    HeyForm has unauthenticated /api/upload endpoint that accepts arbitrary files with no auth/session/form context
    cvelistv5