{"id":"CVE-2026-77763","title":"The filestore backend in pkg/object/file.go, used for file:// stores and as a common juicefs sync destination, derived every operation's target from path(key), which returned either filepath.Join(d.root, key) or filepath.Clean(d.root + k…","summary":"The filestore backend in pkg/object/file.go, used for file:// stores and as a common juicefs sync destination, derived every operation's target from path(key), which returned either filepath.Join(d.root, key) or filepath.Clean(d.root + k…","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N","cwe":["CWE-22"],"vendor":"juicedata","product":"github.com/juicedata/juicefs","affected":["github.com/juicedata/juicefs <= 1.4.1"],"published":"2026-08-21","updated":"2026-09-24","sourceUpdated":"2026-09-24T20:43:32.537","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-77763","references":[{"url":"https://github.com/juicedata/juicefs","label":"disclosure@vulncheck.com"},{"url":"https://github.com/juicedata/juicefs/blob/v1.4.1/pkg/object/file.go","label":"disclosure@vulncheck.com"},{"url":"https://github.com/juicedata/juicefs/commit/0bcd70b3d13088d38127d6fb5750c91be7c4ec16","label":"disclosure@vulncheck.com"},{"url":"https://github.com/juicedata/juicefs/issues/7401","label":"disclosure@vulncheck.com"},{"url":"https://github.com/juicedata/juicefs/pull/7425","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/juicefs-local-filestore-backend-joins-object-keys-onto-the-storage-root-without-a-containment-check-allowing-writes-outside-the-configured-directory","label":"disclosure@vulncheck.com"}],"tags":["nvd","cve.org"],"epss":0.00498,"epssPercentile":0.4001,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-08-21T21:32:48.194454Z"},"ingestedAt":"2026-09-24T15:45:56.699Z","slug":"CVE-2026-77763","body":"## Overview\n\nThe filestore backend in pkg/object/file.go, used for file:// stores and as a common juicefs sync destination, derived every operation's target from path(key), which returned either filepath.Join(d.root, key) or filepath.Clean(d.root + key) with no check that the result stayed beneath the root. Put, Get, Head, Delete, Chmod, Chown, Symlink and Readlink all consumed that value directly. Object keys enumerated from a source object store during a sync are not constrained the way local filesystem names are, so a key containing traversal segments causes juicefs to write attacker-supplied content to a path outside the intended local destination, and no error is returned. An operator syncing from a bucket whose contents they do not fully control, such as a shared or public bucket or one an attacker can write to, is therefore exposed to a file write at an attacker-influenced location. The fix changes path() to return an error and rejects any key whose resolved path escapes the root.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}