GHSA-499r-g7pc-vmp9 is a high-severity (CVSS 7) Path Traversal vulnerability in composer/composer. O3 Security confirms whether GHSA-499r-g7pc-vmp9 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Composer: Arbitrary file write outside vendor via malicious transitive package name
Real-World Exposure
composer/composer🐘composer/composerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Summary
A maliciously crafted package, published on an untrusted third party repository other than Packagist.org or Private Packagist, can cause Composer to write files outside the vendor/ directory and outside your project, with attacker-controlled content, during a normal install or update through using an invalid package name, which was not correctly validated by Composer.
This is an arbitrary file write that can be used to execute code outside the Composer project's context in which you expected the package code to execute (for example by writing shell startup files, SSH authorized_keys, or a cron entry). It is a supply-chain issue: it requires a malicious or compromised package to be present in the dependency graph, it is not otherwise remotely exploitable against a machine.
The fix makes Composer validate every package produced by dependency resolution before anything is written to composer.lock or installed, and abort with a security error if a package name is not a valid vendor/package name.
Am I affected?
You may be affected if you install packages from an untrusted third party repository, which does not sufficiently validate package names. Packagist.org and Private Packagist are safe, as they validate package names correctly.
Patched versions
Fixed in 2.2.29 and 2.10.2. Composer 1.x is also affected and you should move to a safe 2.x release.
Workarounds
Do not use untrusted package repositories. If you have to, mirror them through an internal repository like Private Packagist.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | composer/composer | ≥ 2.3.0&&< 2.10.2 | 2.10.2 |
| 🐘Packagist | composer/composer | ≥ 1.0.0&&< 2.2.29 | 2.2.29 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for composer/composer. 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 composer/composer to 2.10.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-499r-g7pc-vmp9 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-499r-g7pc-vmp9 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-499r-g7pc-vmp9. 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-499r-g7pc-vmp9 in your dependencies?
O3 detects GHSA-499r-g7pc-vmp9 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.