CVE-2026-35198
Stored XSS in HeyForm enabling account takeover when owners view crafted forms.
Is CVE-2026-35198 being exploited?
Not confirmed. CVE-2026-35198 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.49% probability of exploitation in the next 30 days.
How severe is CVE-2026-35198?
CVE-2026-35198 is rated Critical with a CVSS score of 9.0. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-35198?
Yes. A fix has been recorded for CVE-2026-35198. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-35198 affect?
CVE-2026-35198 affects HeyForm < 3.0.0-rc.7, Self-hosted HeyForm installations, Hosted HeyForm deployments. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-35198?
Upgrade to 3.0.0-rc.7+, restrict team privileges, audit forms and credentials.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Low-privileged team member can inject JS in forms; when an owner views it, attacker achieves privilege escalation and full account takeover.
Immediate action required
- affected< 3.0.0-rc.7
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.