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Fencer Vulns
critical 9.3

CVE-2026-54088 json

File Browser: Command Injection via Authentication Hook Shell Substitution (Pre-Authentication RCE)

published 2026-06-25 4 mo ago modified 2026-07-21 3 mo ago also EUVD-2026-39510 , GHSA-m93h-4hw7-5qcm , GO-2026-5962

cvss
9.3
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 55%
public exploits
0
none known

Summary

File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. Prior to 2.63.6, the Hook Authentication feature in File Browser allows administrators to delegate login verification to an external shell command. User-supplied credentials (username and password) are interpolated into this command string using os.Expand without sanitization. An unauthenticated remote attacker can inject shell metacharacters in the username or password field at the login screen, causing the server to execute arbitrary OS commands before any authentication takes place. This is a critical pre-authentication RCE. This vulnerability is fixed in 2.63.6.

Patch / fix

  • go github.com/filebrowser/filebrowser/v2 2.63.6
  • filebrowser filebrowser 2.63.6
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.76% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/filebrowser/filebrowser/security/advisories/GHSA-m93h-4hw7-5qcm referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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 packages

ecosystem package affected fixed in
go github.com/filebrowser/filebrowser/v2
<2.63.6
2.63.6
go github.com/filebrowser/filebrowser
all versions
 no fix listed

Affected products

  • filebrowser filebrowser

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command
  • CWE-88 Improper Neutralization of Argument Delimiters in a Command
  • CWE-306 Missing Authentication for Critical Functionality

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.

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