TI-2026-71185 Aliases CVE-2026-109373 GHSA-ff7c-8692-c559

ZITADEL Login V2 Account Takeover via Unsigned Session Cookie

MEDIUM 42CWE-441Published 2026-10-12 · Updated 2026-10-13

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: Present
Impact type: —
Confidentiality · integrity · availability: High · High · High
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

ZITADEL 3.0.0 before 4.19.2 contains an authentication bypass in the Login V2 UI (CVE-2026-109373, CWE-441) that lets unauthenticated attackers obtain other users' session tokens by forging unsigned session cookies. Attackers guess time-ordered session IDs around a victim's sign-in and submit them with empty tokens to receive rotated tokens, which takes over the account, including MFA-completed administrator sessions. CVSS 4.0 scores it 9.2 (CRITICAL) with no privileges or user interaction required, and CISA has not added it to KEV.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00423 36th percentileScored 2026-11-07

Fix Fixed zitadel (zitadel): 4.19.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
zitadel	zitadel	3.0.0 to before 4.19.2	4.19.2	Patch available	CNA

zitadel Vendorzitadel Affected 3.0.0 to before 4.19.2 Fixed in 4.19.2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:zitadel:zitadel::::::::	—	—	zitadel

cpe:2.3:a:zitadel:zitadel:*:*:*:*:*:*:*:* Versions — — ·zitadel

Remediation

Upgrade ZITADEL to 4.19.2 or later, which fixes the issue.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Fix · CNA zitadel (zitadel) Fixed in 4.19.2

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-10-12
zitadel 4.19.2
3 records Highest priority Priority MEDIUM 2 MEDIUM, 1 LOW
Other records, highest priority first
- TI-2026-71184 Authentication bypass in ZITADEL SAML login enables account takeoverPriority MEDIUM 42
- TI-2026-71186 Privilege escalation in ZITADEL via OIDC token exchange impersonationPriority LOW 23
Show all 3 records →

Timeline

2026-10-12 Threatist record created from CVE-2026-109373
2026-10-12 Alias added: GHSA-ff7c-8692-c559
2026-10-13 CISA SSVC decision points changed

References

Advisory 1

GitHub Security Advisory (GHSA-jh92-5mrj-p2w2)

TI-2024-26607 ZITADEL Vulnerable to Session Information Leakage CVSS 3.1MEDIUM 6.5
TI-2026-67551 ZITADEL before 4.16.2 Account Pre-Hijacking via Forged External IdP Callback CVSS 4.0CRITICAL 9.3
TI-2026-67543 ZITADEL before 4.17.3 Account Takeover via External IdP Linking CVSS 4.0CRITICAL 9.3
TI-2025-41253 ZITADEL Vulnerable to Unauthenticated Full-Read SSRF via V2 Login CVSS 3.1CRITICAL 9.3
TI-2025-39554 Zitadel Bypass Second Authentication Factor CVSS 4.0HIGH 8.7
TI-2026-82647 ZITADEL Login V2 flaw lets attackers approve device authorizations CVSS 4.0HIGH 8.6

See all 77 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences