CVE-2026-105211

ZITADEL before 4.17.1 Authentication Bypass via Login V2 OTP returnCode

HIGH
8.1
CVSS Score
Published: October 4, 2026 at 01:10 PM UTC
Updated: October 5, 2026 at 03:17 PM UTC
1 product affected across 1 vendorZitadel

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Severity
HIGH8.1
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.17.1
Vendor states this is fixed in 4.17.1 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGHVulnCheck
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-200

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