Vulnerability · Published Jul 20, 2026 · Assigned by GitHub_M

CVE-2026-63429HeyForm has unauthenticated /api/upload endpoint that accepts arbitrary files with no auth/session/form context

High 8.6

In plain English

A high-severity missing authentication in heyform from heyform. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities).

Severity (CVSS 3.1)8.6High

Exploit odds (30 days)0.5%top 56.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
heyform	heyform	< 3.0.0-rc.9

Weakness: CWE-306, CWE-434 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

References

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