CVE-2026-45797

Medium

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.

SeverityMedium

CVSS6.4

Exploit probability—

ProductHeyform

PublishedJul 20, 2026

First seenJul 20, 2026

Weakness typeCWE-79Cross-site scripting (XSS)CWE-434Unrestricted upload of dangerous file type

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

Product	Affected versions	Fixed in
heyform heyform	< 3.0.0-rc.7	—

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