CVE-2026-35585: File Browser has a Command Injection via Hook Runner

File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. From 2.0.0 through 2.63.1, the hook system in File Browser — which executes administrator-defined shell commands on file events such as upload, rename, and delete — is vulnerable to OS command injection. Variable substitution for values like $FILE and $USERNAME is performed via os.Expand without sanitization. An attacker with file write permission can craft a malicious filename containing shell metacharacters, causing the server to execute arbitrary OS commands when the hook fires. This results in Remote Code Execution (RCE). This feature has been disabled by default for all installations from v2.33.8 onwards, including for existent installations.