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CVE-2026-40876

Goshs path traversal

8.8 HIGHPublic exploitEPSS 0.59%
  1. Published21 Apr 2026

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Goshs2.0.0 · < 2.0.0

Remediation

Fixed in
Goshs≥ 2.0.0

References

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Frequently asked

Is CVE-2026-40876 being actively exploited?

CVE-2026-40876 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.59%.

How severe is CVE-2026-40876?

CVE-2026-40876 has a CVSS 3.1 base score of 8.8, rated high. EPSS estimates a 0.59% probability of exploitation.

Which products are affected by CVE-2026-40876?

Affected products include Goshs.

How do I fix CVE-2026-40876?

Upgrade affected software to a fixed version, for example Goshs 2.0.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.