{"id":"CVE-2026-102615","aliases":["EUVD-2026-117549","GHSA-pxw5-pjrc-j758"],"status":"published","title":"HeyForm: Uploaded HTML files are served as text/html on the app origin with no CSP — stored XSS","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.","severity":{"version":"3.1","score":7.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00252,"percentile":0.16853,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-79"],"published":"2026-11-05T15:32:30Z","modified":"2026-11-09T22:10:53Z","products":[{"vendor":"heyform","product":"heyform"}],"references":[{"url":"https://github.com/heyform/heyform/security/advisories/GHSA-pxw5-pjrc-j758","tags":["x_refsource_CONFIRM","exploit","advisory"]},{"url":"https://github.com/heyform/heyform/commit/849f7101d4370b29e716b2d7ee14a86c2f598f3a","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/heyform/heyform/releases/tag/v3.0.1","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/102xxx/CVE-2026-102615.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-102615","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-102615","title":"HeyForm: Uploaded HTML files are served as text/html on the app origin with no CSP — stored XSS","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.","status":"published","published":"2026-11-05T15:32:30.406Z","modified":"2026-11-09T22:10:53.78Z","cvss":[{"version":"3.1","score":7.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N","level":"high","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-09T23:35:21.200784Z"}],"euvd":[{"id":"EUVD-2026-117549","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.","status":"published","published":"2026-11-05T15:32:30Z","modified":"2026-11-09T22:10:53Z","cvss":[{"version":"3.1","score":7.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N","level":"high"}],"updated_at":"2026-11-09T23:18:32.235826Z"}],"nvd":[{"id":"CVE-2026-102615","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.","status":"published","published":"2026-11-05T16:17:23.937Z","modified":"2026-11-09T23:17:10.64Z","cvss":[{"version":"3.1","score":7.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N","level":"high","assessor":"secondary"}],"cwes":["CWE-79"],"updated_at":"2026-11-10T02:16:32.753769Z"}],"osv":[{"id":"CVE-2026-102615","title":"HeyForm: Uploaded HTML files are served as text/html on the app origin with no CSP — stored XSS","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.","status":"published","published":"2026-11-05T15:32:30.406Z","modified":"2026-11-11T02:30:56.134165611Z","cvss":[{"version":"3.1","score":7.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N","level":"high"}],"cwes":["CWE-79"],"updated_at":"2026-11-07T03:07:59.573031Z"}]}}