{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-121520", "assignerOrgId": "686469e6-3ff6-451b-ab8b-cf5b9e89401e", "state": "PUBLISHED", "assignerShortName": "Docker", "dateReserved": "2026-11-03T14:26:45.909Z", "datePublished": "2026-11-03T22:11:57.202Z", "dateUpdated": "2026-11-03T22:11:57.202Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "BuildKit", "vendor": "Moby", "repo": "https://github.com/moby/buildkit", "versions": [{"version": "0", "status": "affected", "lessThan": "0.34.1", "versionType": "semver"}]}], "descriptions": [{"lang": "en", "value": "In BuildKit versions prior to v0.34.1, a malicious client with access to the BuildKit control APIs can submit a build request that sets an extended attribute on a file outside the BuildKit state directory. Extended attributes in the trusted. or security. namespaces may also be set, potentially giving a program on the host elevated privileges. This issue affects build services that accept build requests from untrusted users. The issue is fixed in v0.34.1."}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "Host security-label modification"}], "cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:N/SI:H/SA:H", "baseScore": 4.5, "baseSeverity": "MEDIUM"}}], "problemTypes": [{"descriptions": [{"cweId": "CWE-61", "description": "CWE-61: UNIX Symbolic Link (Symlink) Following", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "686469e6-3ff6-451b-ab8b-cf5b9e89401e", "shortName": "Docker", "dateUpdated": "2026-11-03T22:11:57.202Z"}, "references": [{"tags": ["vendor-advisory"], "url": "https://github.com/moby/buildkit/security/advisories/GHSA-w26x-xg27-7qjc"}], "source": {"discovery": "EXTERNAL"}, "title": "Malicious client could set xattr value outside of BuildKit state directory", "solutions": [{"lang": "en", "value": "Upgrade BuildKit to v0.34.1 or later."}], "workarounds": [{"lang": "en", "value": "Restrict access to BuildKit control APIs to trusted clients and do not accept build requests from untrusted users."}]}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "BuildKit", "repo": "https://github.com/moby/buildkit", "vendor": "Moby", "versions": [{"lessThan": "0.34.1", "status": "affected", "version": "0", "versionType": "semver"}]}], "source": "security@docker.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In BuildKit versions prior to v0.34.1, a malicious client with access to the BuildKit control APIs can submit a build request that sets an extended attribute on a file outside the BuildKit state directory. Extended attributes in the trusted. or security. namespaces may also be set, potentially giving a program on the host elevated privileges. This issue affects build services that accept build requests from untrusted users. The issue is fixed in v0.34.1."}], "id": "CVE-2026-121520", "lastModified": "2026-11-03T23:17:34.177", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "LOCAL", "availabilityRequirement": "NOT_DEFINED", "baseScore": 4.5, "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": "HIGH", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "HIGH", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:N/SI:H/SA:H/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": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security@docker.com", "type": "Secondary"}]}, "published": "2026-11-03T23:17:34.177", "references": [{"source": "security@docker.com", "url": "https://github.com/moby/buildkit/security/advisories/GHSA-w26x-xg27-7qjc"}], "sourceIdentifier": "security@docker.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-61"}], "source": "security@docker.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,0.34.1)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "BuildKit", "source": "cna", "vendor": "Moby"}, "product": "buildkit", "vendor": "moby"}], "created": "2026-11-04T02:00:08.480561+00:00", "updated": "2026-11-04T02:00:08.480602+00:00", "vendors": ["moby", "moby$PRODUCT$buildkit"]}