CVE-2026-109371CWE-306

CVE-2026-109371

High · published October 12, 2026

CVSS v3.1
8.2
EPSS
0%
Percentile
29.0
In the wild
Unconfirmed
What it is

ZITADEL 3.0.0 before 4.18.0 contains a missing authentication vulnerability in the hosted Login V1 UI, where the change-username handler acts on the account bound to a login flow before any factor is verified. Unauthenticated attackers can submit a victim's login name and then post a new username to rename any active human user, including administrators, locking them out.

The record
Technical detail
CVSS v3.1
8.2 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
CVSS v4.0
8.8 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
EPSS
0.00363 · 29.0th percentile
Weakness
CWE-306 · Missing Authentication for Critical Function
Published
2026-10-12T21:17Z
References (2)
https://github.com/zitadel/zitadel/security/advisories/GHSA-4hgj-wm6c-q7p2 · [email protected]https://www.vulncheck.com/advisories/zitadel-3.0.0-before-4.18.0-unauthenticated-username-change-via-login-v1 · [email protected]
EPSS history
Timeline
  • 14 OCT 03:27Z
    EPSS moved — → 0%
    epss
  • 12 OCT 16:05Z
    ZITADEL 3.0.0 before 4.18.0 Unauthenticated Username Change via Login V1
    cvelistv5
  • 12 OCT 16:05Z
    ZITADEL 3.0.0 before 4.18.0 Unauthenticated Username Change via Login V1
    cvelistv5