CVE-2026-45797

HeyForm Vulnerable to Stored XSS via Unauthenticated SVG File Upload

State: Published
Severity: 6.4 Medium
Published: Jul 20, 2026
Updated: Jul 20, 2026
Reserved: May 13, 2026

Description

HeyForm is an open-source form builder. Prior to version 3.0.0-rc.7, the `/api/upload` endpoint allows unauthenticated file uploads including SVG files. Uploaded SVGs are stored in the static assets directory and served with `Content-Type: image/svg+xml` by Express's serve-static middleware, allowing an attacker to achieve stored cross-site scripting (XSS) on the heyform domain without any authentication. Version 3.0.0-rc.7 contains a patch for the issue.

Scores

CVSS	Score	Vector	Source
4.0	6.4 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N	GitHub_M

Weaknesses

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-434 Unrestricted Upload of File with Dangerous Type

Affected Products

Product	Versions
heyformheyform	< 3.0.0-rc.7Affected

References

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