CVE-2026-49238
8.4 · HIGHOverview
CVE-2026-49238 is a high-severity vulnerability affecting canonical multipass. It was published on May 28, 2026 and has a CVSS 3.1 base score of 8.4 (HIGH).
This vulnerability has a CVSS 3.1 base score of 8.4, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical Description
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.
Remediation
Check the references section for vendor advisories and patches from canonical. Update multipass to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| canonical | multipass | >= 0, < 1.16.3 | Affected |
Frequently Asked Questions
What is CVE-2026-49238?
CVE-2026-49238 is a high-severity vulnerability affecting canonical multipass. It was published on May 28, 2026 and has a CVSS 3.1 base score of 8.4 (HIGH).
How severe is CVE-2026-49238?
This vulnerability has a CVSS 3.1 base score of 8.4, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-49238?
Check the references section for vendor advisories and patches from canonical. Update multipass to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-49238?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-49238 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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