File Browser: Symlink following lets scoped users read, overwrite, and share files outside their filebrowser scope

Exploitation

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

CVSS

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

EPSS

• CVE-2026-54094: 0.50% estimated exploitation activity in the next 30 days; percentile 43.07 (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 File Browser enforces per-user scope with afero.NewBasePathFs(afero.NewOsFs(), scope), set up in users/users.go. This blocks lexical ../ traversal, but it does not stop the HTTP file handlers from following symbolic links before they open, serve, write, share, or list a file. As a result, a scoped user — and in some cases an unauthenticated public-share recipient — can cross the intended scope boundary by following a symlink whose path is lexically inside their scope but whose target is outside it. Two distinct shapes are covered here: - Variant 1 — symlink as the final path component. A symlink that lives inside the user's scoped tree and points to a file under the server root but outside the scope. The handlers record the symlink (IsSymlink) but then resolve and operate on the target anyway. - Variant 2 — file or directory reached through a symlinked ancestor. A regular file requested through a symlinked directory. Read, write (including TUS resumable uploads), share…

Published by the source

12 Jun 2026, 21:53 UTC

Last modified by the source

12 Jun 2026, 21:53 UTC

Source last checked

26 Oct 2026, 15:23 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-239w-m3h6-ch8v

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# Patch Next advisory brief: CVE-2026-54094

Advisory: File Browser: Symlink following lets scoped users read, overwrite, and share files outside their filebrowser scope
IDs: CVE-2026-54094, GHSA-239w-m3h6-ch8v
Record: https://patchnext.com/advisories/cve-2026-54094 (revision 1, source checked 26 Oct 2026, 15:23 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: github.com/filebrowser/filebrowser/v2 2.63.14. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/filebrowser/filebrowser/v2: affected <= 2.63.13; fixed in 2.63.14
- Go github.com/filebrowser/filebrowser: affected <= 1.11.0

## Suggested inspection (read-only)
- Go github.com/filebrowser/filebrowser/v2: check the installed version with your package manager.
- Go github.com/filebrowser/filebrowser: 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/filebrowser/filebrowser/v2, github.com/filebrowser/filebrowser.
- 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-239w-m3h6-ch8v (GitHub-reviewed advisory GHSA-239w-m3h6-ch8v lists affected ranges: Go github.com/filebrowser/filebrowser/v2 >=0 =0 <=1.11.0)

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