GHSA-fj7f-vq84-fh43
MEDIUMGHSA-fj7f-vq84-fh43 is a medium-severity (CVSS 6.7) CWE-88 vulnerability in bundler. 2 public exploit references exist, so weaponization risk is real. O3 Security confirms whether GHSA-fj7f-vq84-fh43 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Local Code Execution through Argument Injection via dash leading git url parameter in Gemfile.
Blast Radius
bundlerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
In bundler versions before 2.2.33, when working with untrusted and apparently harmless Gemfile's, it is not expected that they lead to execution of external code, unless that's explicit in the ruby code inside the Gemfile itself. However, if the Gemfile includes gem entries that use the git option with invalid, but seemingly harmless, values with a leading dash, this can be false.
To handle dependencies that come from a Git repository instead of a registry, Bundler uses various commands, such as git clone. These commands are being constructed using user input (e.g. the repository URL). When building the
commands, Bundler versions before 2.2.33 correctly avoid Command Injection vulnerabilities by passing an array of arguments instead of a command string. However, there is the possibility that a user input starts with a dash (-) and is therefore treated as an optional argument instead of a positional one. This can lead to Code Execution because some of the commands have options that can be leveraged to run arbitrary executables.
Since this value comes from the Gemfile file, it can contain any character, including a leading dash.
Exploitation
To exploit this vulnerability, an attacker has to craft a directory containing a Gemfile file that declares a dependency that is located in a Git repository. This dependency has to have a Git URL in the form of -u./payload. This URL
will be used to construct a Git clone command but will be interpreted as the upload-pack argument. Then this directory needs to be shared with the victim, who then needs to run a command that evaluates the Gemfile, such as bundle lock, inside.
Impact
This vulnerability can lead to Arbitrary Code Execution, which could potentially lead to the takeover of the system. However, as explained above, the exploitability is very low, because it requires a lot of user interaction. It still could put developers at risk when dealing with untrusted files in a way they think is safe, because the exploit still works when the victim tries to make sure nothing can happen, e.g. by manually reviewing the Gemfile (although they would need the weird URL with a leading dash to not raise any flags).
This kind of attack vector has been used in the past to target security researchers by sending them projects to collaborate on.
Patches
Bundler 2.2.33 has patched this problem by inserting -- as an argument before any positional arguments to those Git commands that were affected by this issue.
Workarounds
Regardless of whether users can upgrade or not, they should review any untrustred Gemfile's before running any bundler commands that may read them, since they can contain arbitrary ruby code.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | bundler | all versions | 2.2.33 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for bundler. 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 bundler to 2.2.33 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fj7f-vq84-fh43 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-fj7f-vq84-fh43 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-fj7f-vq84-fh43. 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-fj7f-vq84-fh43 in your dependencies?
O3 detects GHSA-fj7f-vq84-fh43 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.