GHSA-hc8f-m8g5-8362 CVE-2025-52904 GO-2025-3793
File Browser: Command Execution not Limited to Scope
- Severity
- 8.0 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 1.11%
- Chance of exploitation in the next 30 days. Higher than 66.06% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-77 Improper Neutralization of Special Elements used in a Command ('Command Injection')
- Fix
2.33.8- Upgrade github.com/filebrowser/filebrowser/v2 to this version or later
Description
[!NOTE] This feature has been disabled by default for all installations from v2.33.8 onwards, including for existent installations. To exploit this vulnerability, the instance administrator must turn on a feature and ignore all the warnings about known vulnerabilities. We're publishing this new advisory to make it clear that all vulnerabilities concerning this feature are disclosed.
For more information about tracking vulnerability issues related to the Command Execution features, check https://github.com/filebrowser/filebrowser/issues/5199.
Summary
In the web application, all users have a scope assigned, and they only have access to the files within that scope. The Command Execution feature of Filebrowser allows the execution of shell commands which are not restricted to the scope, potentially giving an attacker read and write access to all files managed by the server.
Impact
Shell commands are executed with the uid of the server process without any further restrictions. This means, that they will have access to at least
- all files managed by the application from all scopes, even those the user does not have access to in the GUI.
- the Filebrowser database file containing the password hashes of all accounts.
The concrete impact depends on the commands being granted to the attacker, but due to other vulnerabilities identified ("Bypass Command Execution Allowlist", "Shell Commands Can Spawn Other Commands", "Insecure File Permissions") it is likely, that full read- and write-access will exist.
Read access to the database means, that the attacker is capable of extracting all user password hashes. This enables an offline dictionary attack on the passwords of all accounts, though the choice of the password hash function (bcrypt with a complexity of 10) gives a strong protection against such attacks. Write access to the database means that attackers are capable of changing a user's password hash, allowing them to impersonate any user account, including an administrator.
Vulnerability Description
Shell commands executed by a user are created as a simple subprocess of the application without any further restrictions. That means, that they have full access to files accessible by the application. The scope that is assigned to every account is not considered.
As a prerequisite, an attacker needs an account with the Execute Commands permission and some permitted commands.
Proof of Concept
Any exploit highly depends on the commands granted to the attacker.
The following screenshot shows, how all password hashes can be extracted using only the grep command:
Recommended Countermeasures
Until this issue is fixed, we 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 application's configuration.
As a defense-in-depth measure, organizations not requiring command execution should operate the Filebrowser from a distroless container image.
There are two approaches to fixing this issue:
- Limiting the process when it is started e.g., by using user namespaces with a tool like Bubblewrap. If this path is chosen, it is important to use a method that works both on a bare-metal server and within an unprivileged container.
- Re-architecting the command execution feature so that file in the various scopes have a distinct uid as an owner and all shell command are executed under the uid of the user's scope.
Timeline
2025-03-26Identified the vulnerability in version 2.32.02025-04-11Contacted the project2025-04-18Vulnerability disclosed to the project2025-06-25Uploaded advisories to the project's GitHub repository2025-06-25CVE ID assigned by GitHub2025-06-25A 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. Fix is tracked on https://github.com/filebrowser/filebrowser/issues/5199.
References
- Sandboxing Applications with Bubblewrap: Securing a Basic Shell
- "Distroless" Container Images.
- Original Advisory
Credits
- Mathias Tausig (SBA Research)
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/filebrowser/filebrowser | all versions |
No fix yet |
| github.com/filebrowser/filebrowser/v2 | < 2.33.8 |
2.33.8 |
| github.com/filebrowser/filebrowser/v2 | all versions |
No fix yet |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/filebrowser/filebrowser/v2 Go → 2.33.8
- go
go get github.com/filebrowser/filebrowser/v2@v2.33.8 && go mod tidy
Severity breakdown
CVSS 3.1 8.0
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- High
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')
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.
How to prevent it
- Architecture and Design: If at all possible, use library calls rather than external processes to recreate the desired functionality.
- Implementation: If possible, ensure that all external commands called from the program are statically created.
- Implementation: 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.
- Operation: Run time: Run time policy enforcement may be used in an allowlist fashion to prevent use of any non-sanctioned commands.
- System Configuration: Assign permissions that prevent the user from accessing/opening privileged files.
References
Advisories
Packages
Other links
- github.com/filebrowser/filebrowser/security/advisories/GHSA-hc8f-m8g5-8362
- github.com/filebrowser/filebrowser/issues/5199
- github.com/GoogleContainerTools/distroless
- github.com/sbaresearch/advisories/tree/public/2025/SBA-ADV-20250326-01_Filebrow…
- pkg.go.dev/vuln/GO-2025-3793
- sloonz.github.io/posts/sandboxing-1
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-833g-cqhp-h72j File Browser: Share API exposes the password hash and bypass token | Low | Also affects github.com/filebrowser/filebrowser |
| GHSA-83xp-526h-j3ww File Browser: Archive builder turns backslash filenames into path traversal (zip-slip) | Medium | Also affects github.com/filebrowser/filebrowser |
| GHSA-7rc3-g7h6-22m7 File Browser: Colliding username normalization gives two users the same home directory | High | Also affects github.com/filebrowser/filebrowser |
| GHSA-8wc8-hf36-mjh9 File Browser: ScopedFs follows a dangling symlink on write, letting a scoped user create files outside their scope | Medium | Also affects github.com/filebrowser/filebrowser |
| GHSA-fmm7-x4gx-8jhr File Browser: Out-of-scope file deletion by a Create-only scoped user via symlink-following RemoveAll in upload failure-cleanup | High | Also affects github.com/filebrowser/filebrowser |
| GHSA-xqp3-jq6g-x3qm File Browser: Authentication Bypass via Proxy Auth Header Forgery | Critical | Also affects github.com/filebrowser/filebrowser |
| GHSA-m93h-4hw7-5qcm File Browser: Command Injection via Authentication Hook Shell Substitution (Pre-Authentication RCE) | Critical | Also affects github.com/filebrowser/filebrowser |
| GHSA-8c9q-7855-wfxq File Browser has a Command Execution Allowlist Bypass via Shell Metacharacter Injection | High | Also affects github.com/filebrowser/filebrowser |
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