What’s Vulnerable › Vulnerabilities

CVE-2026-109373: ZITADEL 3.0.0 before 4.19.2 Account Takeover via Unsigned Login V2 Session Cookie

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-12 · updated 2026-10-13
• Weakness: CWE-441

Description

ZITADEL 3.0.0 before 4.19.2 contains an authentication bypass vulnerability in the Login V2 UI that allows unauthenticated attackers to obtain other users' session tokens by forging unsigned session cookies. Attackers can guess time-ordered session IDs around a victim's sign-in and supply them with empty tokens to receive rotated tokens, taking over accounts including MFA-completed administrator sessions.

Affected products

• zitadel: from 3.0.0 before 4.19.2 — fixed in 4.19.2

How to fix

Upgrade to a fixed version: zitadel 4.19.2. Check the vendor advisory for mitigations.

References

• https://github.com/zitadel/zitadel/security/advisories/GHSA-jh92-5mrj-p2w2
• https://www.vulncheck.com/advisories/zitadel-3.0.0-before-4.19.2-account-takeover-via-unsigned-login-v2-session-cookie

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