File Browser: Out-of-scope file deletion by a Create-only scoped user via symlink-following RemoveAll in upload failure-cleanup

Exploitation

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

CVSS

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

EPSS

• CVE-2026-55667: 0.49% estimated exploitation activity in the next 30 days; percentile 42.47 (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 A scoped, non-admin File Browser user holding only the Create permission can delete arbitrary files outside their scope (other tenants' data, and the application's own database) via the upload failure-cleanup path. This is an incomplete fix of CVE-2026-54094: the v2.63.14 ScopedFs containment wrapper was applied to read/write/list/rename but NOT to the delete path. Confidentiality is preserved (reads stay blocked); integrity and availability are not. ScopedFs.RemoveAll is the one dereferencing operation that skips the symlink guard every other method enforces. The direct-upload handler runs RemoveAll on the user-controlled path during failed-upload cleanup, gated only by Perm.Create. If an escaping directory symlink already exists inside the user's scope, an authenticated create-only user can delete an out-of-scope target, bypassing both the ScopedFs boundary and the Perm.Delete gate. Affected code:…

Published by the source

20 Jul 2026, 21:17 UTC

Last modified by the source

20 Jul 2026, 21:17 UTC

Source last checked

26 Oct 2026, 15:25 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-fmm7-x4gx-8jhr

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# Patch Next advisory brief: CVE-2026-55667

Advisory: File Browser: Out-of-scope file deletion by a Create-only scoped user via symlink-following RemoveAll in upload failure-cleanup
IDs: CVE-2026-55667, GHSA-fmm7-x4gx-8jhr
Record: https://patchnext.com/advisories/cve-2026-55667 (revision 1, source checked 26 Oct 2026, 15:25 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/filebrowser/filebrowser/v2 2.63.16. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/filebrowser/filebrowser/v2: affected <= 2.63.15; fixed in 2.63.16

## Suggested inspection (read-only)
- Go github.com/filebrowser/filebrowser/v2: 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/filebrowser/filebrowser/v2.
- 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-fmm7-x4gx-8jhr (GitHub-reviewed advisory GHSA-fmm7-x4gx-8jhr lists affected ranges: Go github.com/filebrowser/filebrowser/v2 >=0 <=2.63.15)

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