{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-64394", "assignerOrgId": "36234546-b8fa-4601-9d6f-f4e334aa8ea1", "state": "PUBLISHED", "assignerShortName": "hackerone", "dateReserved": "2025-10-31T15:00:01.447Z", "datePublished": "2026-10-27T16:16:58.979Z", "dateUpdated": "2026-10-27T16:16:58.979Z"}, "containers": {"cna": {"descriptions": [{"lang": "en", "value": "A vulnerability allowing a low-privileged local user to write arbitrary files with SYSTEM privileges during the installation of Veeam Backup for Microsoft 365, which can lead to privilege escalation or denial of service."}], "affected": [{"defaultStatus": "unaffected", "vendor": "Veeam", "product": "Backup for Microsoft 365", "versions": [{"version": "8.0", "status": "affected", "lessThanOrEqual": "8.6.0.1102", "versionType": "semver"}]}], "references": [{"url": "https://www.veeam.com/kb4957"}], "metrics": [{"cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N", "baseScore": 4.3, "baseSeverity": "MEDIUM"}}], "problemTypes": [{"descriptions": [{"type": "CWE", "lang": "en", "cweId": "CWE-1386", "description": "CWE-1386 Insecure Operation on Windows Junction / Mount Point"}]}], "providerMetadata": {"orgId": "36234546-b8fa-4601-9d6f-f4e334aa8ea1", "shortName": "hackerone", "dateUpdated": "2026-10-27T16:16:58.979Z"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Backup for Microsoft 365", "vendor": "Veeam", "versions": [{"lessThanOrEqual": "8.6.0.1102", "status": "affected", "version": "8.0", "versionType": "semver"}]}], "source": "support@hackerone.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "A vulnerability allowing a low-privileged local user to write arbitrary files with SYSTEM privileges during the installation of Veeam Backup for Microsoft 365, which can lead to privilege escalation or denial of service."}], "id": "CVE-2025-64394", "lastModified": "2026-10-27T17:16:53.867", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "LOCAL", "availabilityRequirement": "NOT_DEFINED", "baseScore": 4.3, "baseSeverity": "MEDIUM", "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": "LOW", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "ACTIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:N/VI:L/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", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "support@hackerone.com", "type": "Secondary"}]}, "published": "2026-10-27T17:16:53.867", "references": [{"source": "support@hackerone.com", "url": "https://www.veeam.com/kb4957"}], "sourceIdentifier": "support@hackerone.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-1386"}], "source": "support@hackerone.com", "type": "Secondary"}]}

{}

{"created": "2026-10-27T18:00:08.795712+00:00", "title": "Privilege Escalation in Veeam Backup for Microsoft 365 via Installation File Write", "updated": "2026-10-27T18:00:08.795720+00:00", "vendors": []}