# CVE-2026-40188: goshs is Missing Write Protection for Parametric Data Values

> An attacker can write files outside the SFTP root directory due to insufficient sanitization of the destination path in the rename command.

- **Severity:** High 7.7 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Apr 2026
- **Updated:** 13 Apr 2026
- **Also known as:** GHSA-2943-crp8-38xx, GO-2026-4953

## What is CVE-2026-40188?

CVE-2026-40188 is a high-severity path traversal vulnerability in patrickhener goshs, published on 10 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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.

Weakness: CWE-1314 (Missing Write Protection for Parametric Data Values)

## Which versions are affected by CVE-2026-40188?

3 open source packages ship an affected version, including github.com/patrickhener/goshs. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/patrickhener/goshs` | Go | From 1.0.7 | None |
| `github.com/patrickhener/goshs` | Go | From 1.0.7 to 1.1.4 | None |
| `github.com/patrickhener/goshs` | Go | From 1.0.7 to 1.1.4 | None |

Products: Goshs Goshs.

## How do I fix CVE-2026-40188?

Upgrade to a fixed version.

## Is CVE-2026-40188 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40188 exists.

## Other vulnerabilities in patrickhener goshs

- [CVE-2026-40884](https://insights.sbomify.com/CVE-2026-40884/): goshs: Empty-username SFTP password authentication bypass in goshs (critical 9.8)
- [CVE-2026-35392](https://insights.sbomify.com/CVE-2026-35392/): goshs has an Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in goshs PUT Upload (critical 9.8)
- [CVE-2026-35393](https://insights.sbomify.com/CVE-2026-35393/): Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in goshs POST multipart upload (critical 9.8)
- [CVE-2026-35471](https://insights.sbomify.com/CVE-2026-35471/): Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in goshs (critical 9.8)
- [CVE-2026-40189](https://insights.sbomify.com/CVE-2026-40189/): goshs has a file-based ACL authorization bypass in goshs state-changing routes (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40188 and fix it if it is affected.

What it is: CVE-2026-40188 is a high-severity path traversal vulnerability in patrickhener goshs, published on 10 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40188 exists.

Affected packages and fixed versions:
- github.com/patrickhener/goshs (Go): affected from 1.0.7; no fix listed
- github.com/patrickhener/goshs (Go): affected from 1.0.7 up to 1.1.4; no fix listed
- github.com/patrickhener/goshs (Go): affected from 1.0.7 up to 1.1.4; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-40188/ (Markdown: https://insights.sbomify.com/CVE-2026-40188/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40188
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40188
- OSV: https://osv.dev/vulnerability/CVE-2026-40188

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40188/
Summaries are generated and may contain mistakes; the official description above is the record.