---
id: CVE-2026-49238
title: An issue was discovered in Canonical Multipass before version 1.16.3
summary: >-
  An issue was discovered in Canonical Multipass before version 1.16.3. The
  host-side SFTP server component (sshfs_server), which executes with root
  privileges on the host, contains a path containment bypass vulnerability
  within its valida…
severity: high
cvss: 8.4
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N'
cwe:
  - CWE-22
vendor: canonical
product: multipass
affected:
  - multipass < 1.16.3
patched:
  - multipass 1.16.3
published: '2026-05-28'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T20:10:00.190'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-49238'
references:
  - url: >-
      https://github.com/canonical/multipass/security/advisories/GHSA-rhp2-23c4-r34w
    label: security@ubuntu.com
  - url: >-
      https://github.com/canonical/multipass/security/advisories/GHSA-rhp2-23c4-r34w
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00446
epssPercentile: 0.37238
ingestedAt: '2026-10-14T20:53:12.337Z'
---

## Overview

An issue was discovered in Canonical Multipass before version 1.16.3. The host-side SFTP server component (sshfs_server), which executes with root privileges on the host, contains a path containment bypass vulnerability within its validate_path function in src/sshfs_mount/sftp_server.cpp. The function performs a plain string prefix comparison on requested paths without path separator validation or dot-dot (..) normalization. A local attacker with root privileges inside a guest virtual machine can bypass the FUSE layer by injecting raw SFTP frames (such as an SSH_FXP_OPEN request) directly into the sshfs_server process stdin/stdout pipes via procfs. By supplying a path containing directory traversal sequences that match the allowed mount prefix, the attacker can force the host-side root process to resolve the traversal and open files outside the designated mount boundary. This allows a guest-side user to read arbitrary files on the host filesystem, resulting in a virtual machine escape.

## Affected

- `multipass < 1.16.3`

## Remediation

Upgrade past the affected range:

- `multipass 1.16.3`