CVE-2025-52903

File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, preview, rename and edit files. In version 2.32.0, the Command Execution feature of File Browser only allows the execution of shell command which have been predefined on a user-specific allowlist. Many tools allow the execution of arbitrary different commands, rendering this limitation void. The concrete impact depends on the commands being granted to the attacker, but the large number of standard commands allowing the execution of subcommands makes it likely that every user having the Execute commands permissions can exploit this vulnerability. Everyone who can exploit it will have full code execution rights with the uid of the server process. Until this issue is fixed, the maintainers recommend to completely disable Execute commands for all accounts. Since the command execution is an inherently dangerous feature that is not used by all deployments, it should be possible to completely disable it in the applications configuration. As a defense-in-depth measure, organizations not requiring command execution should operate the Filebrowser from a distroless container image. A patch version has been pushed to disable the feature for all existent installations, and making it opt-in. A warning has been added to the documentation and is printed on the console if the feature is enabled. Due to the project being in maintenance-only mode, the bug has not been fixed. The fix is tracked on pull request 5199.

Weakness

The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.

Extended Description

Command injection vulnerabilities typically occur when:

Many protocols and products have their own custom command language. While OS or shell command strings are frequently discovered and targeted, developers may not realize that these other command languages might also be vulnerable to attacks. Command injection is a common problem with wrapper programs.

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/136.html
• https://cwe.mitre.org/data/definitions/15.html
• https://cwe.mitre.org/data/definitions/183.html
• https://cwe.mitre.org/data/definitions/248.html
• https://cwe.mitre.org/data/definitions/40.html
• https://cwe.mitre.org/data/definitions/43.html
• https://cwe.mitre.org/data/definitions/75.html
• https://cwe.mitre.org/data/definitions/76.html

References

• https://github.com/GoogleContainerTools/distroless
• https://github.com/filebrowser/filebrowser/issues/5199
• https://github.com/filebrowser/filebrowser/security/advisories/GHSA-3q2w-42mv-cph4
• https://manpages.debian.org/bookworm/util-linux/prlimit.1.en.html
• https://github.com/filebrowser/filebrowser/security/advisories/GHSA-3q2w-42mv-cph4