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Fencer Vulns
high 8.6

CVE-2026-116682 json

FileBrowser Quantum: Symlink following escapes user scope allowing arbitrary file read outside the served directory

published 2026-10-27 12 d ago modified 2026-11-05 3 d ago also GHSA-mgqf-5mf5-prfj , GO-2026-6870 , EUVD-2026-111279

cvss
8.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

FileBrowser Quantum is a free, self-hosted, web-based file manager. Prior to 1.5.2-stable and 2.0.1-beta, file read handling in backend/pkg/indexing/indexingFiles.go resolves symbolic links through GetRealPath without confirming that the resolved target remains inside the source root and the user's authorized scope. Download, preview, media, OnlyOffice, and public-share read flows that enable FollowSymlinks can therefore serve an out-of-scope target through a reachable in-scope symlink. An authenticated user with download access can read server-accessible files outside the assigned scope, and a holder of a public share link can do the same without an account when the shared directory exposes such a symlink. This issue is fixed in 1.5.2-stable and 2.0.1-beta.

Patch / fix

  • go github.com/gtsteffaniak/filebrowser/backend 0.0.0-20260814233832-4126edeb07a0

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
6 d ago

Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/gtsteffaniak/filebrowser/security/advisories/GHSA-mgqf-5mf5-prfj referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
GitHub 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
go github.com/gtsteffaniak/filebrowser/backend
<0.0.0-20260814233832-4126edeb07a0
0.0.0-20260814233832-4126edeb07a0

Affected products

  • gtsteffaniak filebrowser

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-59 Improper Link Resolution Before File Access

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.