Path Traversal in Goshs
CVE-2026-40876
goshs is a SimpleHTTPServer written in Go. Prior to 2.0.0-beta.6, goshs contains an SFTP root escape caused by prefix-based path validation. An authenticated SFTP user can read from and write to filesystem paths outside the configured SFTP root, which breaks the intended jail boundary and can expose or modify unrelated server files. The SFTP subsystem routes requests through sftpserver/sftpserver.go into DefaultHandler.GetHandler() in sftpserver/handler.go, which forwards file operations into readFile, writeFile, listFile, and cmdFile. All of those sinks rely on sanitizePath() in sftpserver/helper.go. helper.go uses a raw string-prefix comparison, not a directory-boundary check. Because of that, if the configured root is /tmp/goshsroot, then a sibling path such as /tmp/goshsroot_evil/secret.txt incorrectly passes validation since it starts with the same byte prefix. This vulnerability is fixed in 2.0.0-beta.6.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.006 (46.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 46.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002
Affected products
- Goshs — versions 2.0.0
- Patrickhener Goshs — versions < 2.0.0-beta.6
Weakness classification (CWE)
References
- github.com/patrickhener/goshs/security/advisories/GHSA-5h6h-7rc9-3824 (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-40876?
- CVE-2026-40876 is a high-severity vulnerability in Goshs, classified under Path Traversal. CVSS score: 8.8/10. Published 2026-04-21.
- How severe is CVE-2026-40876?
- High severity. CVSS v3 base score is 8.8 out of 10.