---
cve: "CVE-2026-49991"
severity: "HIGH"
cvss: 8.6
epss: "27%"
vendor: "rustfs"
kev: false
exploited: false
published: "2026-06-26 20:17:17"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-18T04:55:28+02:00"
---

# CVE-2026-49991

> 8.6 HIGH · 🧪 PoC

## Beschreibung

RustFS is a distributed object storage system built in Rust. In 1.0.0-beta.4, authenticated users with only PutObject permission on their own bucket can exploit a path traversal vulnerability in the Snowball auto-extract feature to write arbitrary objects into other users' buckets, completely breaking multi-tenant isolation. The vulnerability chains three flaws: No ../ sanitization in tar entry key normalization; IAM wildcard matching uses raw (uncleaned) paths; and Filesystem path cleaning resolves ../ across bucket boundaries.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Keine | good |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Keine | good |

## Referenzen

- <https://github.com/rustfs/rustfs/security/advisories/GHSA-f4vq-9ffr-m8m3>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-49991) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_