{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-56857", "assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc", "state": "PUBLISHED", "assignerShortName": "Go", "dateReserved": "2026-06-23T15:10:49.353Z", "datePublished": "2026-10-08T22:53:58.387Z", "dateUpdated": "2026-10-08T22:53:58.387Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc", "shortName": "Go", "dateUpdated": "2026-10-08T22:53:58.387Z"}, "title": "Root.Mkdir(All) can follow junctions out of the root on Windows in os", "descriptions": [{"lang": "en", "value": "On Windows, when the target of Root.Mkdir or Root.MkdirAll is a junction pointing to an empty location, the operation can create a directory at the junction target even when that target is located outside the root. This only applies to operations where the last path component is a junction (path/to/junction, but not path/junction/target)."}], "affected": [{"vendor": "Go standard library", "product": "os", "collectionURL": "https://pkg.go.dev", "packageName": "os", "versions": [{"version": "0", "lessThan": "1.26.9", "status": "affected", "versionType": "semver"}, {"version": "1.27.0-0", "lessThan": "1.27.2", "status": "affected", "versionType": "semver"}], "platforms": ["windows"], "programRoutines": [{"name": "Root.Mkdir"}, {"name": "doInRoot"}, {"name": "rootMkdirAll"}, {"name": "Root.Chmod"}, {"name": "Root.Chown"}, {"name": "Root.Chtimes"}, {"name": "Root.Lchown"}, {"name": "Root.Link"}, {"name": "Root.MkdirAll"}, {"name": "Root.Remove"}, {"name": "Root.RemoveAll"}, {"name": "Root.Rename"}, {"name": "Root.Symlink"}], "defaultStatus": "unaffected"}, {"vendor": "Go standard library", "product": "internal/syscall/windows", "collectionURL": "https://pkg.go.dev", "packageName": "internal/syscall/windows", "versions": [{"version": "0", "lessThan": "1.26.9", "status": "affected", "versionType": "semver"}, {"version": "1.27.0-0", "lessThan": "1.27.2", "status": "affected", "versionType": "semver"}], "platforms": ["windows"], "programRoutines": [{"name": "Mkdirat"}], "defaultStatus": "unaffected"}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "CWE-1386: Insecure Operation on Windows Junction / Mount Point"}]}], "references": [{"url": "https://go.dev/cl/847305"}, {"url": "https://go.dev/issue/81739"}, {"url": "https://groups.google.com/g/golang-announce/c/U2fTuyDJznI"}, {"url": "https://pkg.go.dev/vuln/GO-2026-6604"}], "credits": [{"lang": "en", "value": "Daniele Ballarini"}]}}}

{}

{"affected": [{"affectedData": [{"collectionURL": "https://pkg.go.dev", "defaultStatus": "unaffected", "packageName": "os", "platforms": ["windows"], "product": "os", "programRoutines": [{"name": "Root.Mkdir"}, {"name": "doInRoot"}, {"name": "rootMkdirAll"}, {"name": "Root.Chmod"}, {"name": "Root.Chown"}, {"name": "Root.Chtimes"}, {"name": "Root.Lchown"}, {"name": "Root.Link"}, {"name": "Root.MkdirAll"}, {"name": "Root.Remove"}, {"name": "Root.RemoveAll"}, {"name": "Root.Rename"}, {"name": "Root.Symlink"}], "vendor": "Go standard library", "versions": [{"lessThan": "1.26.9", "status": "affected", "version": "0", "versionType": "semver"}, {"lessThan": "1.27.2", "status": "affected", "version": "1.27.0-0", "versionType": "semver"}]}, {"collectionURL": "https://pkg.go.dev", "defaultStatus": "unaffected", "packageName": "internal/syscall/windows", "platforms": ["windows"], "product": "internal/syscall/windows", "programRoutines": [{"name": "Mkdirat"}], "vendor": "Go standard library", "versions": [{"lessThan": "1.26.9", "status": "affected", "version": "0", "versionType": "semver"}, {"lessThan": "1.27.2", "status": "affected", "version": "1.27.0-0", "versionType": "semver"}]}], "source": "security@golang.org"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "On Windows, when the target of Root.Mkdir or Root.MkdirAll is a junction pointing to an empty location, the operation can create a directory at the junction target even when that target is located outside the root. This only applies to operations where the last path component is a junction (path/to/junction, but not path/junction/target)."}], "id": "CVE-2026-56857", "lastModified": "2026-10-08T23:17:01.487", "metrics": {}, "published": "2026-10-08T23:17:01.487", "references": [{"source": "security@golang.org", "url": "https://go.dev/cl/847305"}, {"source": "security@golang.org", "url": "https://go.dev/issue/81739"}, {"source": "security@golang.org", "url": "https://groups.google.com/g/golang-announce/c/U2fTuyDJznI"}, {"source": "security@golang.org", "url": "https://pkg.go.dev/vuln/GO-2026-6604"}], "sourceIdentifier": "security@golang.org", "vulnStatus": "Received"}

{}

{"created": "2026-10-09T01:00:14.864199+00:00", "updated": "2026-10-09T01:00:14.864208+00:00", "vendors": [], "weaknesses": ["CWE-22"]}