CVE-2025-52904 — v2
HIGHCVE-2025-52904 is a high-severity (CVSS 8) CWE-77 vulnerability in github.com/filebrowser/filebrowser/v2. A fix is available for github.com/filebrowser/filebrowser/v2 — see the affected versions and patch details below.
File Browser: Command Execution not Limited to Scope
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-52904.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-52904 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/filebrowser/filebrowser/v2Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/filebrowser/filebrowser/v2 | all versions | 2.33.8go get github.com/filebrowser/filebrowser/v2@v2.33.8 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/filebrowser/filebrowser/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/filebrowser/filebrowser/v2 to 2.33.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-52904 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-52904 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-52904. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-52904 in your dependencies?
O3 Security finds CVE-2025-52904 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.