What is CVE-2026-82291?

CVE-2026-82291 is a high-severity vulnerability in Heyform, classified under Permissive Cross-domain Policy with Untrusted Domains. CVSS score: 8.1/10. Published 2026-08-28.

How severe is CVE-2026-82291?

High severity. CVSS v3 base score is 8.1 out of 10.

Vulnerability in Heyform

CVE-2026-82291

HeyForm before 3.0.0-rc.8 reflects the request Origin header in CORS responses while allowing credentials, enabling cross-origin requests with authentication. Attackers can execute authenticated GraphQL queries from malicious pages visited by logged-in users to access workspaces, projects, forms, submissions, and respondent data, or modify account settings.

Published 2026-08-28 · last modified 2026-09-16.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.006 (44.6th percentile), scored 2026-10-13.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 44.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.006 · change: +0.003

Affected products

Heyform

Weakness classification (CWE)

CWE-942 — Permissive Cross-domain Policy with Untrusted Domains

References

GitHub Security Advisory (GHSA-fg7j-rmgr-rc9g) (vendor-advisory)
Vulnerable code: main.ts (technical-description)
Fix commit (patch)
github.com/heyform/heyform (product)
VulnCheck Advisory: HeyForm Reflects Any Origin in CORS Responses While Allowing Credentials (third-party-advisory)

Frequently asked questions

What is CVE-2026-82291?: CVE-2026-82291 is a high-severity vulnerability in Heyform, classified under Permissive Cross-domain Policy with Untrusted Domains. CVSS score: 8.1/10. Published 2026-08-28.
How severe is CVE-2026-82291?: High severity. CVSS v3 base score is 8.1 out of 10.