{"id":"CVE-2026-77763","aliases":["EUVD-2026-63899","GHSA-2pgv-c2r7-f43r"],"status":"published","title":"JuiceFS Local Filestore Backend Joins Object Keys onto the Storage Root Without a Containment Check, Allowing Writes Outside the Configured Directory","description":"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 + 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.","severity":{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00498,"percentile":0.43134,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-22"],"published":"2026-08-21T11:05:13Z","modified":"2026-11-09T02:47:16Z","products":[{"vendor":"juicedata","product":"juicefs"}],"references":[{"url":"https://github.com/juicedata/juicefs/issues/7401","tags":["issue-tracking","report"]},{"url":"https://github.com/juicedata/juicefs/commit/0bcd70b3d13088d38127d6fb5750c91be7c4ec16","tags":["patch","fix"]},{"url":"https://github.com/juicedata/juicefs/pull/7425","tags":["issue-tracking","patch","fix"]},{"url":"https://github.com/juicedata/juicefs/blob/v1.4.1/pkg/object/file.go","tags":["technical-description","article"]},{"url":"https://github.com/juicedata/juicefs","tags":["product","package"]},{"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","tags":["third-party-advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-77763","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-2pgv-c2r7-f43r"},{"url":"https://proxy.golang.org","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77763.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-77763","title":"JuiceFS Local Filestore Backend Joins Object Keys onto the Storage Root Without a Containment Check, Allowing Writes Outside the Configured Directory","description":"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 + 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.","status":"published","published":"2026-08-21T11:05:13.65Z","modified":"2026-11-08T14:08:56.782Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","level":"high","assessor":"cna"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-22"],"updated_at":"2026-11-08T15:43:34.234229Z"}],"euvd":[{"id":"EUVD-2026-63899","description":"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 + 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.","status":"published","published":"2026-08-21T11:05:13Z","modified":"2026-11-08T14:08:56Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-08T15:13:06.469155Z"}],"ghsa":[{"id":"GHSA-2pgv-c2r7-f43r","title":"The filestore backend in pkg/object/file.go, used for file:// stores and as a common juicefs sync...","description":"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 + 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.","status":"published","published":"2026-08-21T12:30:32Z","modified":"2026-08-21T12:30:33Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/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","level":"high"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N","level":"medium"}],"cwes":["CWE-22"],"updated_at":"2026-11-02T15:10:49.498684Z"}],"nvd":[{"id":"CVE-2026-77763","description":"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 + 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.","status":"published","published":"2026-08-21T11:17:06.937Z","modified":"2026-10-16T15:10:00.103Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/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","level":"high","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-22"],"updated_at":"2026-11-02T14:12:40.665005Z"}],"osv":[{"id":"CVE-2026-77763","title":"JuiceFS Local Filestore Backend Joins Object Keys onto the Storage Root Without a Containment Check, Allowing Writes Outside the Configured Directory","description":"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 + 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.","status":"published","published":"2026-08-21T11:05:13.65Z","modified":"2026-11-09T02:47:16.66341308Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-22"],"updated_at":"2026-11-09T03:16:17.543303Z"}]}}