File Browser: FilePath traversal in download-as-zip/tar via Windows-style backslash separators in stored filenames

Exploitation

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

CVSS 4.0

6.2 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:N/SI:H/SA:L · score source

EPSS

• CVE-2026-54093: 0.19% estimated exploitation activity in the next 30 days; percentile 9.05 (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 filebrowser builds the download-as-zip / download-as-tar archive entry names with filepath.ToSlash, which on a Linux host is a no-op for backslashes (\ is only a path separator on Windows). A file whose name contains Windows-style traversal (..\..\..\evil.txt) is accepted by the resource handlers, stored on the Linux filesystem with a literal backslash name, and then emitted verbatim as the archive entry name. Windows extractors (Explorer, 7-Zip, WinRAR, .NET ZipFile.ExtractToDirectory) interpret \ as a path separator and write the extracted file outside the extraction directory — arbitrary file write on the victim who downloads and extracts the archive. Details http/raw.go getFiles() constructs the in-archive name and passes it to github.com/mholt/archives@v0.1.5: On Linux filepath.Separator == '/', so filepath.ToSlash leaves any literal backslash in the stored filename untouched. mholt/archives nameOnDiskToNameInArchive then writes that name verbatim into the zip/tar…

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-gxjx-7m74-hcq8

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# Patch Next advisory brief: CVE-2026-54093

Advisory: File Browser: FilePath traversal in download-as-zip/tar via Windows-style backslash separators in stored filenames
IDs: CVE-2026-54093, GHSA-gxjx-7m74-hcq8
Record: https://patchnext.com/advisories/cve-2026-54093 (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 6.2)
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 2.63.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/filebrowser/filebrowser/v2: affected <= 2.63.5; fixed in 2.63.6
- 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-gxjx-7m74-hcq8 (GitHub-reviewed advisory GHSA-gxjx-7m74-hcq8 lists affected ranges: Go github.com/filebrowser/filebrowser/v2 >=0 =0 <=1.11.0)

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