patrickhener goshs up to 2.0.0-beta.5 sftpserver/sftpserver.go DefaultHandler.GetHandler path traversal

Summaryinfo

A vulnerability, which was classified as critical, has been found in patrickhener goshs up to 2.0.0-beta.5. This affects the function DefaultHandler.GetHandler of the file sftpserver/sftpserver.go. Performing a manipulation results in path traversal. This vulnerability is cataloged as CVE-2026-40876. It is possible to initiate the attack remotely. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in patrickhener goshs up to 2.0.0-beta.5. This affects the function DefaultHandler.GetHandler of the file sftpserver/sftpserver.go. The manipulation with an unknown input leads to a path traversal vulnerability. CWE is classifying the issue as CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-40876 since 04/15/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1006 for this issue.

Upgrading to version 2.0.0-beta.6 eliminates this vulnerability.

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Productinfo

Vendor

• patrickhener

Name

• goshs

Version

• 2.0.0-beta.0
• 2.0.0-beta.1
• 2.0.0-beta.2
• 2.0.0-beta.3
• 2.0.0-beta.4
• 2.0.0-beta.5

Website

• Product: https://github.com/patrickhener/goshs/

CPE 2.3info

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CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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