Most recent entries from all

EUVD-2026-328111

2026-10-12T21:31:11.305432+00:00

EUVD-2026-328111

fkie_cve-2026-48777

2026-10-12T21:31:11.305459+00:00

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.

GHSA-qqqm-5547-774x — FileBrowser Quantum: Path traversal in public share PATCH allows file ops outside shared directory

2026-10-12T21:31:11.305500+00:00

Affected: Go: github.com/gtsteffaniak/filebrowser/backend

## Summary

`publicPatchHandler` in `backend/http/public.go` 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.

Verified on commit 869b640 (HEAD of `main` as of 2026-05-07).

## Details

In `backend/http/public.go` the public PATCH handler accepts a JSON body with `items[].fromPath` and `items[].toPath` from the client, then prepends the share path before delegating to `resourcePatchHandler`:

```go // backend/http/public.go (publicPatchHandler) for i := range req.Items { req.Items[i].FromSource = sourceName req.Items[i].FromPath = utils.JoinPathAsUnix(d.share.Path, req.Items[i].FromPath) // line 372 req.Items[i].ToSource = sourceName req.Items[i].ToPath = utils.JoinPathAsUnix(d.share.Path, req.Items[i].ToPath) // line 374 } d.Data = req status, err := resourcePatchHandler(w, r, d) ```

`utils.JoinPathAsUnix` is a thin w…