goshs has a file-based ACL authorization bypass in goshs state-changing routes

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

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 · score source

EPSS

• CVE-2026-40189: 0.64% estimated exploitation activity in the next 30 days; percentile 50.88 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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. Details The project README explicitly documents file-based ACLs as a security feature: - README.md:59 - "You can place a .goshs in any folder to apply custom ACLs" - README.md:61 - "You can apply custom basic auth per folder" The read/list path correctly enforces .goshs: - httpserver/filebased.go:10-49 loads .goshs - httpserver/handler.go:68-91…

Published by the source

10 Apr 2026, 20:00 UTC

Last modified by the source

15 Apr 2026, 21:06 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-wvhv-qcqf-f3cx

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# Patch Next advisory brief: CVE-2026-40189

Advisory: goshs has a file-based ACL authorization bypass in goshs state-changing routes
IDs: CVE-2026-40189, GHSA-wvhv-qcqf-f3cx
Record: https://patchnext.com/advisories/cve-2026-40189 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/patrickhener/goshs: affected <= 1.1.4

## Suggested inspection (read-only)
- Go github.com/patrickhener/goshs: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/patrickhener/goshs.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-wvhv-qcqf-f3cx (GitHub-reviewed advisory GHSA-wvhv-qcqf-f3cx lists affected ranges: Go github.com/patrickhener/goshs >=0 <=1.1.4)

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