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.
https://github.com/heyform/heyform/security/advisories/GHSA-m94h-jxvc-hhch
https://github.com/heyform/heyform/commit/144240e5545d10fd9e120d05ccb402a6d7064674
Published: 2026-07-20
Updated: 2026-07-20
Base Score: 3.5
Vector: CVSS2#AV:N/AC:M/Au:S/C:N/I:P/A:N
Severity: Low
Base Score: 5.4
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Severity: Medium
Base Score: 6.4
Vector: 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
Severity: Medium