CVE-2026-63429

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

HIGH
8.6
CVSS Score
Published: July 20, 2026 at 03:54 PM UTC
Updated: July 22, 2026 at 09:04 PM UTC
1 product affected across 1 vendorHeyForm

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Severity
HIGH8.6
Exploit prediction
EPSS 0.5%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.0.0-rc.9
Affected range stops below 3.0.0-rc.9, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.6HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
HIGH
Availability
LOW
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-306CWE-434

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