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

> Attackers can bypass MFA in ZITADEL Login V2 by reusing sessions, allowing unauthorized access to customer applications via OIDC or SAML callbacks.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Sep 2026
- **Updated:** 28 Sep 2026
- **Also known as:** GHSA-9993-rfwp-rhwf, GO-2026-6589

## What is CVE-2026-85056?

CVE-2026-85056 is a high-severity authentication bypass vulnerability in zitadel, published on 24 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-85056?

3 open source packages ship an affected version, including github.com/zitadel/zitadel.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/zitadel/zitadel` | Go | All versions | 1.80.0-v2.20.0.20260717062356-56f4798ed31f |
| `github.com/zitadel/zitadel` | Go | All versions | 1.80.0-v2.20.0.20260717062356-56f4798ed31f |
| `github.com/zitadel/zitadel` | Go | All versions | 1.80.0-v2.20.0.20260717062356-56f4798ed31f |

## How do I fix CVE-2026-85056?

Upgrade github.com/zitadel/zitadel to 1.80.0-v2.20.0.20260717062356-56f4798ed31f or later.

## Is CVE-2026-85056 being exploited?

There is no known exploitation of CVE-2026-85056 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-85056 and fix it if it is affected.

What it is: CVE-2026-85056 is a high-severity authentication bypass vulnerability in zitadel, published on 24 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-85056 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/zitadel/zitadel (Go): affected all versions; fixed in 1.80.0-v2.20.0.20260717062356-56f4798ed31f
- github.com/zitadel/zitadel (Go): affected all versions; fixed in 1.80.0-v2.20.0.20260717062356-56f4798ed31f
- github.com/zitadel/zitadel (Go): affected all versions; fixed in 1.80.0-v2.20.0.20260717062356-56f4798ed31f

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-85056/ (Markdown: https://insights.sbomify.com/CVE-2026-85056/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-85056
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-85056
- OSV: https://osv.dev/vulnerability/CVE-2026-85056

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-85056/
Summaries are generated and may contain mistakes; the official description above is the record.