CVE-2026-102615: high-severity vulnerability in heyform
HeyForm: Uploaded HTML files are served as text/html on the app origin with no CSP — stored XSS
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.6epss 0.3%
HeyForm is an open-source form builder. Prior to 3.0.1, /api/upload accepts a file according to the client-controlled multipart file.mimetype while retaining an HTML filename, and static/upload serves the resulting file as text/html with contentSecurityPolicy: false. An ordinary user can therefore upload active HTML that executes on the HeyForm origin when a victim opens its returned URL. The same-origin script can access /graphql with the victim's session and read or modify data available to that account. The code also permits upload requests tied to an active public form through formId, openToken, and a fieldId belonging to a file or signature question, although the advisory did not fully verify that unauthenticated path end to end. This issue is fixed in version 3.0.1.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N
Affected products
heyform · heyformRelated CVEs — heyform
In the same product, most dangerous first.
CVE-2026-45797MEDIUMHeyForm Vulnerable to Stored XSS via Unauthenticated SVG File UploadEPSS 0.6%CVE-2026-82291HIGHHeyForm Reflects Any Origin in CORS Responses While Allowing CredentialsEPSS 0.6%CVE-2026-63429HIGHHeyForm has unauthenticated /api/upload endpoint that accepts arbitrary files with no auth/session/form contextEPSS 0.5%CVE-2026-35198CRITICALHeyForm vulnerable to stored XSS via form field titlesEPSS 0.5%CVE-2026-63428MEDIUMHeyForm: completeSubmission persists submitter-supplied hidden fields verbatim without validating against the form's declared hidden-field setEPSS 0.3%