What is CVE-2026-35198?

CVE-2026-35198 is a critical-severity vulnerability in Heyform, classified under Cross-site Scripting. CVSS score: 9.0/10. Published 2026-07-20.

How severe is CVE-2026-35198?

Critical severity. CVSS v3 base score is 9.0 out of 10.

XSS in Heyform

CVE-2026-35198

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 v…

Vulnerability class: XSS (Cross-Site Scripting)

CVSS v3 metric

CVSS v3 base score 9.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H.

Affected products

Heyform — versions < 3.0.0-rc.7

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

security-advisories@github.com (x_refsource_MISC)
security-advisories@github.com (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-35198?: CVE-2026-35198 is a critical-severity vulnerability in Heyform, classified under Cross-site Scripting. CVSS score: 9.0/10. Published 2026-07-20.
How severe is CVE-2026-35198?: Critical severity. CVSS v3 base score is 9.0 out of 10.