ZITADEL before 4.17.1 contains an authentication bypass vulnerability in Login V2 that allows unauthenticated attackers to take over accounts by obtaining OTP codes via the returnCode delivery type. Attackers knowing a login name of a victim with OTP-Email and OTP-SMS enrolled can read both codes from server-action responses to gain MFA-authenticated sessions, including administrator takeover.

Attack Vector Network

Attack Complexity High

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
zitadel zitadel unaffected
Version Status Constraints
0 affected < 4.17.1
4.17.1 unaffected —

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Project Subscriptions

Vendors Products
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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/zitadel/zitadel/security/advisories/GHSA-3gwm-5wx8-4gm6 cve-icon cve-icon
https://www.vulncheck.com/advisories/zitadel-before-4.17.1-authentication-bypass-via-login-v2-otp-returncode cve-icon cve-icon
History

Sun, 04 Oct 2026 14:30:00 +0000

Type Values Removed Values Added
Description ZITADEL before 4.17.1 contains an authentication bypass vulnerability in Login V2 that allows unauthenticated attackers to take over accounts by obtaining OTP codes via the returnCode delivery type. Attackers knowing a login name of a victim with OTP-Email and OTP-SMS enrolled can read both codes from server-action responses to gain MFA-authenticated sessions, including administrator takeover.
Title ZITADEL before 4.17.1 Authentication Bypass via Login V2 OTP returnCode
First Time appeared Zitadel
Zitadel zitadel
Weaknesses CWE-200
CPEs cpe:2.3:a:zitadel:zitadel:*:*:*:*:*:*:*:*
Vendors & Products Zitadel
Zitadel zitadel
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.2, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-04T13:10:04.626Z

Reserved: 2026-10-04T13:02:21.188Z

Link: CVE-2026-105211

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-04T15:16:32.333

Modified: 2026-10-04T15:16:32.467

Link: CVE-2026-105211

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-04T15:30:16Z

Weaknesses