---
id: CVE-2026-49991
title: RustFS is a distributed object storage system built in Rust
summary: >-
  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…
severity: high
cvss: 8.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N'
cwe:
  - CWE-22
  - CWE-862
published: '2026-06-26'
updated: '2026-06-29'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-49991'
references:
  - url: 'https://github.com/rustfs/rustfs/security/advisories/GHSA-f4vq-9ffr-m8m3'
    label: security-advisories@github.com
  - url: 'https://github.com/rustfs/rustfs/security/advisories/GHSA-f4vq-9ffr-m8m3'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00415
epssPercentile: 0.35499
ingestedAt: '2026-06-29T14:29:18.249Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.