---
cve: "CVE-2026-77763"
severity: "HIGH"
cvss: 7.1
epss: "0.3%"
vendor: "juicedata"
kev: false
exploited: false
published: "2026-08-21 11:17:06"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-25T01:59:46+02:00"
---

# CVE-2026-77763

> 7.1 HIGH · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
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
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |

## Patch verfügbar (OSV)

- 0bcd70b3d13088d38127d6fb5750c91be7c4ec16 (Commit)

## Referenzen

- <https://github.com/juicedata/juicefs/issues/7401>
- <https://github.com/juicedata/juicefs/commit/0bcd70b3d13088d38127d6fb5750c91be7c4ec16>
- <https://github.com/juicedata/juicefs/pull/7425>
- <https://github.com/juicedata/juicefs/blob/v1.4.1/pkg/object/file.go>
- <https://github.com/juicedata/juicefs>
- <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>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-77763) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_