gtsteffaniak filebrowser prior 1.3.3-stable/1.4.2-beta backend/http/public.go path traversal

Summaryinfo

A vulnerability marked as critical has been reported in gtsteffaniak filebrowser. Affected is an unknown function of the file backend/http/public.go. Performing a manipulation results in path traversal. This vulnerability was named CVE-2026-48777. The attack may be initiated remotely. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in gtsteffaniak filebrowser. This affects an unknown code of the file backend/http/public.go. The manipulation with an unknown input leads to a path traversal vulnerability. CWE is classifying the issue as CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

FileBrowser Quantum is a free, self-hosted, web-based file manager. Versions prior to 1.3.2-stable, 1.4.0-beta and 1.4.1-beta are vulnerable to Path Traversal through the publicPatchHandler in backend/http/public.go which joins user-controlled fromPath and toPath body fields with the trusted d.share.Path BEFORE the downstream sanitizer runs. Because filepath.Join collapses .. segments during the join, the sanitizer in resourcePatchHandler never sees the traversal and the move/copy/rename operates on a path outside the shared directory. The same root-cause pattern was patched for the bulk DELETE endpoint as CVE-2026-44542 (GHSA-fwj3-42wh-8673), but the PATCH handler with the identical pattern was not updated. A public share link with AllowModify=true is sufficient to exploit this. Anyone holding such a link can move, copy, or rename arbitrary files within the share owner's source root. This issue has been fixed in versions 1.3.3-stable and 1.4.2-beta.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-48777 since 05/22/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1006 according to MITRE ATT&CK.

Upgrading to version 1.3.3-stable or 1.4.2-beta eliminates this vulnerability.

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Productinfo

Vendor

• gtsteffaniak

Name

• filebrowser

Website

• Product: https://github.com/gtsteffaniak/filebrowser/

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