FileBrowser Public Share DELETE API Path Traversal Allows Unauthenticated Arbitrary File Deletion

Exploitation

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

CVSS

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

EPSS

• CVE-2026-44542: 0.52% estimated exploitation activity in the next 30 days; percentile 44.42 (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 Attacker-controlled path input is joined with a trusted base path prior to sanitization, allowing traversal sequences (e.g., ../) to escape the intended shared directory. As a result, an unauthenticated attacker possessing a valid public share hash with delete permissions enabled can delete arbitrary files outside the shared directory within the share owner’s configured storage scope. Affected Components Two distinct vulnerable code paths: 1. Stable versions (e.g., gtstef/filebrowser:stable) DELETE /public/api/resources?hash=<hash&path=../victim Root cause: middleware.go:111 Issue: path query parameter is joined before SanitizeUserPath() 2. Development / HEAD (e.g., commit eabdfd9) DELETE /public/api/resources/bulk?hash=<hash Body: [{"path":"../victim"}] Root cause: resource.go:274 Issue: item.Path is joined before SanitizeUserPath() Steps to reproduce (Stable Version) 1. Create a directory structure: 2. Create a public share: 3. Send request: Proof of Concept (HEAD / bulk…

Published by the source

7 May 2026, 03:28 UTC

Last modified by the source

14 May 2026, 20:54 UTC

Source last checked

26 Oct 2026, 15:22 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-fwj3-42wh-8673

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# Patch Next advisory brief: CVE-2026-44542

Advisory: FileBrowser Public Share DELETE API Path Traversal Allows Unauthenticated Arbitrary File Deletion
IDs: CVE-2026-44542, GHSA-fwj3-42wh-8673
Record: https://patchnext.com/advisories/cve-2026-44542 (revision 1, source checked 26 Oct 2026, 15:22 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/gtsteffaniak/filebrowser 0.0.0-20260501183844-112740bdd41d. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/gtsteffaniak/filebrowser: affected < 0.0.0-20260501183844-112740bdd41d; fixed in 0.0.0-20260501183844-112740bdd41d

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

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/gtsteffaniak/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-fwj3-42wh-8673 (GitHub-reviewed advisory GHSA-fwj3-42wh-8673 lists affected ranges: Go github.com/gtsteffaniak/filebrowser >=0 <0.0.0-20260501183844-112740bdd41d)

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