{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "3.0.0"
              },
              {
                "fixed": "4.18.0"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "573c96d6af6aa8778efd9bff59f9bc0dab94c495"
            },
            {
              "fixed": "6d7878a2e4128517684f43ba7774dd4a9f64ba36"
            }
          ],
          "repo": "https://github.com/zitadel/zitadel",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-4hgj-wm6c-q7p2"
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-306"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109371.json"
  },
  "details": "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.",
  "id": "CVE-2026-109371",
  "modified": "2026-10-13T02:30:45.759805211Z",
  "published": "2026-10-12T16:05:44.304Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109371.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/zitadel/zitadel/security/advisories/GHSA-4hgj-wm6c-q7p2"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-109371"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/zitadel-3.0.0-before-4.18.0-unauthenticated-username-change-via-login-v1"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "ZITADEL 3.0.0 before 4.18.0 Unauthenticated Username Change via Login V1"
}