CVE-2026-109373

ZITADEL 3.0.0 before 4.19.2 Account Takeover via Unsigned Login V2 Session Cookie

State: Published
Severity: 9.2 Critical
Published: Oct 12, 2026
Updated: Oct 13, 2026
Reserved: Oct 12, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	9.2 Critical	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N	VulnCheck
3.1	8.1 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H	VulnCheck

Weaknesses

CWE-441 Unintended Proxy or Intermediary ('Confused Deputy')

Affected Products

Product	Versions
zitadelzitadel	3.0.0 to before 4.19.2Affected 4.19.2Not affected

References

GitHub Security Advisory (GHSA-jh92-5mrj-p2w2)vendor-advisory
VulnCheck Advisory: ZITADEL 3.0.0 before 4.19.2 Account Takeover via Unsigned Login V2 Session Cookiethird-party-advisory

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