CVE-2026-105207

{
  "id": "CVE-2026-105207",
  "sourceIdentifier": "[email protected]",
  "published": "2026-10-04T15:16:31.677",
  "lastModified": "2026-10-29T21:17:09.417",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "ZITADEL 3.0.0 through 3.4.15 and 4.0.0 before 4.17.3 creates links between user accounts and external identity providers without verifying a primary factor or the caller's permission, including on identify-only Login V2 sessions and via the User Service V2 AddIDPLink endpoint. An unauthenticated attacker knowing a victim's login name can bind their own external IdP identity to the victim's account and then sign in as the victim."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "zitadel",
          "product": "zitadel",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "4.0.0",
              "lessThan": "4.17.3",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "4.17.3",
              "versionType": "semver",
              "status": "unaffected"
            }
          ]
        },
        {
          "vendor": "zitadel",
          "product": "zitadel",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "3.0.0",
              "lessThanOrEqual": "3.4.15",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "baseScore": 9.3,
          "baseSeverity": "CRITICAL",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "HIGH",
          "vulnAvailabilityImpact": "HIGH",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "subAvailabilityImpact": "NONE",
          "exploitMaturity": "NOT_DEFINED",
          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-06T21:58:30.918285Z",
          "id": "CVE-2026-105207",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-306"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/zitadel/zitadel/security/advisories/GHSA-g8gj-gq47-xgf4",
      "source": "[email protected]"
    },
    {
      "url": "https://www.vulncheck.com/advisories/zitadel-before-4.17.3-account-takeover-via-external-idp-linking",
      "source": "[email protected]"
    }
  ]
}