filebrowser File Browser up to 2.63.1 FILE/USERNAME os command injection

Summaryinfo

A vulnerability, which was classified as critical, was found in filebrowser File Browser up to 2.63.1. Affected by this issue is some unknown functionality. Executing a manipulation of the argument FILE/USERNAME can lead to os command injection. This vulnerability is registered as CVE-2026-35585. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in filebrowser File Browser up to 2.63.1. It has been declared as critical. This vulnerability affects some unknown functionality. The manipulation of the argument FILE/USERNAME with an unknown input leads to a os command injection vulnerability. The CWE definition for the vulnerability is CWE-78. The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. From 2.0.0 until 2.33.8, 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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-35585 since 04/03/2026. The exploitation appears to be easy. The attack can be initiated remotely. The exploitation requires an enhanced level of successful authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 06/09/2026). The MITRE ATT&CK project declares the attack technique as T1202.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• filebrowser

Name

• File Browser

Version

• 2.63.0
• 2.63.1

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