{"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":"2026-10-09T15:36:01.712Z"},"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"}]},"adp":[{"problemTypes":[{"descriptions":[{"type":"CWE","cweId":"CWE-1386","lang":"en","description":"CWE-1386 Insecure Operation on Windows Junction / Mount Point"}]}],"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":9.8,"attackVector":"NETWORK","baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-10-09T15:35:58.663117Z","id":"CVE-2026-56857","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-10-09T15:36:01.712Z"}}]}}