CVE-2026-109371

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-109371", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-10-12T14:23:25.691Z", "datePublished": "2026-10-12T16:05:44.304Z", "dateUpdated": "2026-10-15T02:55:04.399Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-10-12T16:05:44.304Z"}, "datePublic": "2026-09-24T00:00:00.000Z", "title": "ZITADEL 3.0.0 before 4.18.0 Unauthenticated Username Change via Login V1", "descriptions": [{"lang": "en", "value": "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."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "Missing Authentication for Critical Function", "cweId": "CWE-306", "type": "CWE"}]}], "affected": [{"vendor": "zitadel", "product": "zitadel", "defaultStatus": "unaffected", "packageURL": "pkg:golang/github.com/zitadel/zitadel", "versions": [{"version": "3.0.0", "status": "affected", "versionType": "semver", "lessThan": "4.18.0"}, {"version": "4.18.0", "status": "unaffected", "versionType": "semver"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:zitadel:zitadel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.0.0", "versionEndExcluding": "4.18.0"}]}]}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "vectorString": "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", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 8.8, "baseSeverity": "HIGH"}}, {"format": "CVSS", "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "LOW", "baseScore": 8.2, "baseSeverity": "HIGH"}}], "references": [{"url": "https://github.com/zitadel/zitadel/security/advisories/GHSA-4hgj-wm6c-q7p2", "tags": ["vendor-advisory"], "name": "GitHub Security Advisory (GHSA-4hgj-wm6c-q7p2)"}, {"name": "VulnCheck Advisory: ZITADEL 3.0.0 before 4.18.0 Unauthenticated Username Change via Login V1", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/zitadel-3.0.0-before-4.18.0-unauthenticated-username-change-via-login-v1"}], "credits": [{"lang": "en", "value": "muhlemmer", "type": "finder"}, {"lang": "en", "value": "grvijayan", "type": "finder"}, {"lang": "en", "value": "IAM-marco", "type": "finder"}, {"lang": "en", "value": "AdamKorcz", "type": "reporter"}], "x_generator": {"engine": "vulncheck-endgame"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-10-15T02:54:54.525845Z", "id": "CVE-2026-109371", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-15T02:55:04.399Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-109371", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-15T02:54:54.525845Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-15T02:54:59.992Z"}}], "cna": {"title": "ZITADEL 3.0.0 before 4.18.0 Unauthenticated Username Change via Login V1", "credits": [{"lang": "en", "type": "finder", "value": "muhlemmer"}, {"lang": "en", "type": "finder", "value": "grvijayan"}, {"lang": "en", "type": "finder", "value": "IAM-marco"}, {"lang": "en", "type": "reporter", "value": "AdamKorcz"}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "baseScore": 8.8, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "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", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE"}}, {"format": "CVSS", "cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.2, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "LOW", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}}], "affected": [{"vendor": "zitadel", "product": "zitadel", "versions": [{"status": "affected", "version": "3.0.0", "lessThan": "4.18.0", "versionType": "semver"}, {"status": "unaffected", "version": "4.18.0", "versionType": "semver"}], "packageURL": "pkg:golang/github.com/zitadel/zitadel", "defaultStatus": "unaffected"}], "datePublic": "2026-09-24T00:00:00.000Z", "references": [{"url": "https://github.com/zitadel/zitadel/security/advisories/GHSA-4hgj-wm6c-q7p2", "name": "GitHub Security Advisory (GHSA-4hgj-wm6c-q7p2)", "tags": ["vendor-advisory"]}, {"url": "https://www.vulncheck.com/advisories/zitadel-3.0.0-before-4.18.0-unauthenticated-username-change-via-login-v1", "name": "VulnCheck Advisory: ZITADEL 3.0.0 before 4.18.0 Unauthenticated Username Change via Login V1", "tags": ["third-party-advisory"]}], "x_generator": {"engine": "vulncheck-endgame"}, "descriptions": [{"lang": "en", "value": "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."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-306", "description": "Missing Authentication for Critical Function"}]}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:zitadel:zitadel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "4.18.0", "versionStartIncluding": "3.0.0"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-10-12T16:05:44.304Z"}}}, "cveMetadata": {"cveId": "CVE-2026-109371", "state": "PUBLISHED", "dateUpdated": "2026-10-15T02:55:04.399Z", "dateReserved": "2026-10-12T14:23:25.691Z", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "datePublished": "2026-10-12T16:05:44.304Z", "assignerShortName": "VulnCheck"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "packageURL": "pkg:golang/github.com/zitadel/zitadel", "product": "zitadel", "vendor": "zitadel", "versions": [{"lessThan": "4.18.0", "status": "affected", "version": "3.0.0", "versionType": "semver"}, {"status": "unaffected", "version": "4.18.0", "versionType": "semver"}]}], "source": "disclosure@vulncheck.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "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", "lastModified": "2026-10-15T03:17:10.390", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 8.2, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 4.2, "source": "disclosure@vulncheck.com", "type": "Secondary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "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/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", "version": "4.0", "vulnAvailabilityImpact": "LOW", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "disclosure@vulncheck.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-109371", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-10-15T02:54:54.525845Z", "version": "2.0.3"}}]}, "published": "2026-10-12T17:17:34.547", "references": [{"source": "disclosure@vulncheck.com", "url": "https://github.com/zitadel/zitadel/security/advisories/GHSA-4hgj-wm6c-q7p2"}, {"source": "disclosure@vulncheck.com", "url": "https://www.vulncheck.com/advisories/zitadel-3.0.0-before-4.18.0-unauthenticated-username-change-via-login-v1"}], "sourceIdentifier": "disclosure@vulncheck.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-306"}], "source": "disclosure@vulncheck.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.0.0,4.18.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "4.18.0"}}], "enrichment": {"confidence": 95.0, "confidence_source": "inferred", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "zitadel", "source": "cna", "vendor": "zitadel"}, "product": "zitadel", "vendor": "zitadel"}], "created": "2026-10-12T19:15:14.903792+00:00", "updated": "2026-10-12T22:15:15.549519+00:00", "vendors": ["zitadel", "zitadel$PRODUCT$zitadel"]}