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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| heyform | heyform | affected |
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Advisories
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Fixes
Solution
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Workaround
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References
History
Thu, 05 Nov 2026 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | HeyForm: Uploaded HTML files are served as text/html on the app origin with no CSP — stored XSS | |
| Weaknesses | CWE-79 | |
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| Metrics |
cvssV3_1
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Projects
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MITRE
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-11-05T15:32:30.406Z
Reserved: 2026-09-29T14:18:02.921Z
Link: CVE-2026-102615
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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Weaknesses