{"id":"CVE-2026-49238","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-49238","generatedAt":"2026-10-28T03:32:24.541Z","title":"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.","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.","published":"2026-05-28T14:16:24.000Z","lastModified":"2026-10-14T20:10:00.000Z","status":"Analyzed","sourceIdentifier":"security@ubuntu.com","cvss":{"version":"3.1","score":8.4,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N"},"cwe":["CWE-22"],"affected":["canonical/multipass"],"epss":{"score":0.00505,"percentile":0.42955,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.51%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/canonical/multipass/security/advisories/GHSA-rhp2-23c4-r34w","tags":["Exploit","Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://github.com/canonical/multipass/security/advisories/GHSA-rhp2-23c4-r34w","tags":["Exploit","Third Party Advisory"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-49238","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}