CVE-2026-40876
SFTP root escape via prefix-based path validation in goshs
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Public exploit
A reference of the record is tagged as an exploit or proof of concept: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.
- https://github.com/patrickhener/goshs/security/advisories/GHSA-5h6h-7rc9-3824 (opens in a new tab)x_refsource_CONFIRMexploit
Timeline
ID reserved
By GitHub_M
- 6 days later
· 6 days later
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | High8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| NVDNVD · Analyzed | 4.0 | High8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.44% · top 62% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.7.
Weakness
Affected products
- affected < 2.0.0-beta.6
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Gogithub.com/patrickhener/goshsGHSA-5h6h-7rc9-3824 (opens in a new tab)
- Gogithub.com/patrickhener/goshs/v2GHSA-5h6h-7rc9-3824 (opens in a new tab)
References (1)
- https://github.com/patrickhener/goshs/security/advisories/GHSA-5h6h-7rc9-3824 (opens in a new tab)x_refsource_CONFIRMexploit
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-5h6h-7rc9-3824 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-40876)Record last updated .