Vulnerability Description
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.
Related Weaknesses (CWE)
References
- https://github.com/gtsteffaniak/filebrowser/releases/tag/v1.3.3-stable
- https://github.com/gtsteffaniak/filebrowser/releases/tag/v1.4.2-beta
- https://github.com/gtsteffaniak/filebrowser/security/advisories/GHSA-qqqm-5547-7
- https://github.com/gtsteffaniak/filebrowser/security/advisories/GHSA-qqqm-5547-7
FAQ
What is CVE-2026-48777?
CVE-2026-48777 is a documented vulnerability. 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...
How severe is CVE-2026-48777?
CVSS scoring is not yet available for CVE-2026-48777. Check NVD for updates.
Is there a patch for CVE-2026-48777?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.