CVE-2026-109373

EUVD-2026-97671
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.
Confused Deputy
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
VulnCheckCNA
8.1 HIGH
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
zitadelzitadel
3.0.0 ≤
𝑥
< 4.19.2
CNA
Common Weakness Enumeration
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