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Fencer Intel
medium 6.8

CVE-2026-72835 json

filebrowser before v2.63.21 Access Rule Bypass via Path Canonicalization

published 3mo ago modified 2mo ago also EUVD-2026-58649 , GHSA-fgm5-pw99-w2p7

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository filebrowser/filebrowser. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
6.8
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 43%
public exploits
0
none known

Summary

filebrowser versions before v2.63.21 fail to canonicalize paths before evaluating access rules, allowing authenticated users to bypass administrator-defined deny rules using case-variant or backslash-separated paths. Attackers can request files with alternate path representations that match no rule but resolve to the same filesystem object, gaining unauthorized access to denied files within their scope.

Patch / fix

  • filebrowser filebrowser 2.63.21

Is CVE-2026-72835 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/filebrowser/filebrowser/security/advisories/GHSA-fgm5-pw99-w2p7 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 7.6 CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
CNA 4.0 7.6 CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • filebrowser filebrowser

Classification

Weakness
  • CWE-41 Improper Resolution of Path Equivalence

References

Sources

Fencer Intel 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.

The maintainers of filebrowser/filebrowser published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.