Is CVE-2026-35198 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-35198 being exploited in the wild.

How severe is CVE-2026-35198?

Critical severity, with a CVSS score of 9, published 20 July 2026.

Is there a fix for CVE-2026-35198?

A patch was published on 2026-05-15: Fix committed to repository Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-35198 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-35198?

Check whether you run HeyForm at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-35198: HeyForm stored XSS in form builder field titles

CVE-2026-35198 · Severity: critical · CVSS 9 · Published 2026-07-20

HeyForm is an open-source platform used to build and manage online forms. A security flaw allows a team member with low-level access to inject malicious code into a form's title or description. When a team owner views that form, the code automatically runs in their browser, allowing the attacker to take full control of the account, access sensitive form data, and lock out legitimate users.

Technologies: HeyForm. Vendors: HeyForm.

Quick answers

Is CVE-2026-35198 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-35198 being exploited in the wild.
How severe is CVE-2026-35198?: Critical severity, with a CVSS score of 9, published 20 July 2026.
Which products and versions are affected?: HeyForm < 3.0.0-rc.7.
Is there a fix for CVE-2026-35198?: A patch was published on 2026-05-15: Fix committed to repository Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-35198 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-35198?: Check whether you run HeyForm at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A stored cross-site scripting (XSS) vulnerability exists in HeyForm's form builder component due to improper sanitization of user-controlled input. Specifically, the 'updateFormSchemas' GraphQL mutation allows users to submit arbitrary HTML/JavaScript in form field titles and descriptions, which are subsequently rendered using 'innerHTML' in 'Block.tsx'. An attacker with low-privileged team access can inject a payload that, when viewed by a team owner, executes in the owner's context. This can be leveraged to perform administrative actions, such as calling the 'transferTeam' mutation to escalate privileges and achieve full account takeover. The issue is resolved in version 3.0.0-rc.7 by implementing input sanitization and safe rendering practices.

Affected products

heyform HeyForm < 3.0.0-rc.7

Timeline

2026-05-15: patched: Fix committed to repository
2026-07-02: advisory: GitHub Security Advisory published
2026-07-20: disclosed: CVE published to NVD

References

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