ZITADEL: MFA bypass via session reuse in Login V2

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.2 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

EPSS

• CVE-2026-85056: 0.29% estimated exploitation activity in the next 30 days; percentile 21.13 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A vulnerability in ZITADEL’s Login V2 UI allowed a password-verified browser session to be reused for a new authentication request without re-checking a user’s enrolled second factor (TOTP, OTP, or U2F). An attacker who already knows valid credentials can fully authenticate to an application without completing MFA. Impact ZITADEL Login V2 issues a session as soon as the user’s password is verified, before the MFA challenge is completed. If the MFA step is abandoned (for example by navigating back) and login is started again, Login V2 may reuse that existing session instead of requiring the second factor. Session validity checks only enforced MFA verification when the organization’s login policy had Force MFA (or Force MFA for local users only) enabled. They did not treat a voluntarily enrolled second factor as required. In the common case where MFA is available on the user but not organization-mandated, a password-only session was treated as fully authenticated and used to…

Published by the source

24 Sep 2026, 18:19 UTC

Last modified by the source

1 Oct 2026, 20:45 UTC

Source last checked

26 Oct 2026, 15:29 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-9993-rfwp-rhwf

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6589

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-9993-rfwp-rhwf

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-85056

Advisory: ZITADEL: MFA bypass via session reuse in Login V2
IDs: CVE-2026-85056, GHSA-9993-rfwp-rhwf
Record: https://patchnext.com/advisories/cve-2026-85056 (revision 3, source checked 26 Oct 2026, 15:29 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/zitadel/zitadel 1.80.0-v2.20.0.20260717062356-56f4798ed31f. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/zitadel/zitadel: affected < 1.80.0-v2.20.0.20260717062356-56f4798ed31f; fixed in 1.80.0-v2.20.0.20260717062356-56f4798ed31f

## Suggested inspection (read-only)
- Go github.com/zitadel/zitadel: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/zitadel/zitadel.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GO-2026-6589 (OSV record GO-2026-6589 lists affected ranges: Go github.com/zitadel/zitadel >=0 <1.80.0-v2.20.0.20260717062356-56f4798ed31f (fixed))
- Verified: https://osv.dev/vulnerability/GHSA-9993-rfwp-rhwf (OSV record GHSA-9993-rfwp-rhwf lists affected ranges: Go github.com/zitadel/zitadel >=0 <1.80.0-v2.20.0.20260717062356-56f4798ed31f (fixed))
- Verified: https://github.com/advisories/GHSA-9993-rfwp-rhwf (GitHub-reviewed advisory GHSA-9993-rfwp-rhwf lists affected ranges: Go github.com/zitadel/zitadel >=0 <1.80.0-v2.20.0.20260717062356-56f4798ed31f)

Commands are suggestions: review each one before running it.