CVE-2026-54088

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

State: Published
Severity: 9.3 Critical
Published: Jun 25, 2026
Updated: Jun 25, 2026
Reserved: Jun 11, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
4.0	9.3 Critical	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	GitHub_M

Weaknesses

CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CWE-88 Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
CWE-306 Missing Authentication for Critical Function

Affected Products

Product	Versions
filebrowserfilebrowser	< 2.63.6Affected

References

https://github.com/filebrowser/filebrowser/security/advisories/GHSA-m93h-4hw7-5qcm

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