# CVE-2026-105215: ZITADEL before 4.16.2 Account Pre-Hijacking via Forged External IdP Callback

> Unauthenticated attackers can pre-create accounts bound to victim identities via forged IdP callbacks, leading to account takeover when victims log in.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** GHSA-639g-x9rp-hw3x, GHSA-738m-7888-jfv8

## What is CVE-2026-105215?

CVE-2026-105215 is a critical authentication bypass vulnerability in zitadel, published on 4 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ZITADEL before 3.4.14 and 4.x before 4.16.2 contains an authentication bypass in the hosted Login V1 UI because the 'external account not found' registration endpoint trusts client-supplied external identity fields without a completed IdP callback. Unauthenticated attackers can submit forged IDPConfigID and ExternalUserID values to pre-create an account bound to a victim's external IdP identity, which the victim's later genuine external login then signs into.

Weakness: CWE-290 (Authentication Bypass by Spoofing)

## Which versions are affected by CVE-2026-105215?


## How do I fix CVE-2026-105215?

No fix has been published for CVE-2026-105215 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-105215 being exploited?

There is no known exploitation of CVE-2026-105215 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-105215 and fix it if it is affected.

What it is: CVE-2026-105215 is a critical authentication bypass vulnerability in zitadel, published on 4 Oct 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-2026-105215 in the wild and no public exploit code.

Affected product: zitadel. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-105215/ (Markdown: https://insights.sbomify.com/CVE-2026-105215/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-105215
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-105215
- OSV: https://osv.dev/vulnerability/CVE-2026-105215

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-105215/
Summaries are generated and may contain mistakes; the official description above is the record.