---
title: "CVE-2026-40189: goshs has a file-based ACL authorization bypass in goshs state-changing routes"
url: https://erroneo.us/security/cve/CVE-2026-40189/
description: "CVE-2026-40189 (github.com/patrickhener/goshs (Go)): goshs is a SimpleHTTPServer written in Go. Prior to 2.0.0-beta.4, goshs enforces the documented…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-04-10
date_modified: 2026-04-15
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-40189"
kev: false
cvss: 9.3
epss: 0.0066
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-40189: goshs has a file-based ACL authorization bypass in goshs state-changing routes

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.7% , percentile 51: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 51% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes github.com/patrickhener/goshs (Go) <= 1.1.4, no fixed version listed . Check your lockfile, including transitive dependencies.

## What it is

goshs is a SimpleHTTPServer written in Go. Prior to 2.0.0-beta.4, goshs enforces the documented per-folder .goshs ACL/basic-auth mechanism for directory listings and file reads, but it does not enforce the same authorization checks for state-changing routes. An unauthenticated attacker can upload files with PUT, upload files with multipart POST /upload, create directories with ?mkdir, and delete files with ?delete inside a .goshs-protected directory. By deleting the .goshs file itself, the attacker can remove the folder's auth policy and then access previously protected content without credentials. This results in a critical authorization bypass affecting confidentiality, integrity, and availability. This vulnerability is fixed in 2.0.0-beta.4.

## Affected packages

- Go `github.com/patrickhener/goshs` <= 1.1.4 → fixed: none listed

## Affected products (CVE record)

- patrickhener goshs: < 2.0.0-beta.4

## Severity

- GitHub_M CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`
- GitHub CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.66% probability of exploitation activity in the next 30 days; percentile 51.

## Sources

- [GitHub Advisory GHSA-wvhv-qcqf-f3cx](https://github.com/advisories/GHSA-wvhv-qcqf-f3cx)
- [CVE.org record CVE-2026-40189](https://www.cve.org/CVERecord?id=CVE-2026-40189)
- [NVD entry CVE-2026-40189](https://nvd.nist.gov/vuln/detail/CVE-2026-40189)
- [github.com](https://github.com/patrickhener/goshs/security/advisories/GHSA-wvhv-qcqf-f3cx)
- [github.com](https://github.com/patrickhener/goshs/commit/f212c4f4a126556bab008f79758e21a839ef2c0f)
- [github.com](https://github.com/patrickhener/goshs/releases/tag/v2.0.0-beta.4)

---
Source page: https://erroneo.us/security/cve/CVE-2026-40189/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt