CVE-2026-63429
HIGHHeyForm has unauthenticated /api/upload endpoint that accepts arbitrary files with no auth/session/form context
Description
HeyForm is an open-source form builder. Prior to version 3.0.0-rc.9, POST /api/upload has no authentication guard, no global guard, no form-context validation, no openToken requirement, and no session cookie check. Any anonymous internet user can upload files (PDF, DOC/DOCX, XLS/XLSX, CSV, TXT, MP4, images, etc., up to 10 MB) and receive a permanent public URL on the HeyForm domain. The endpoint is used by both authenticated form creators and unauthenticated form submitters; because no form-context binding exists, every request to it is anonymously accepted. Version 3.0.0-rc.9 contains a patch for the issue.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-63429 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-63429 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-63429. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-63429 in your dependencies?
O3 detects CVE-2026-63429 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.