GHSA-j893-m93w-jwjw
HIGHfast-filesystem-mcp has a Path Traversal vulnerability
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
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
fast-filesystem-mcpnpmDescription
fast-filesystem-mcp version 3.4.0 contains a critical path traversal vulnerability in its file operation tools including fast_read_file. This vulnerability arises from improper path validation that fails to resolve symbolic links to their actual physical paths. The safePath and isPathAllowed functions use path.resolve() which does not handle symlinks, allowing attackers to bypass directory access restrictions by creating symlinks within allowed directories that point to restricted system paths. When these symlinks are accessed through valid path references, the validation checks are circumvented, enabling access to unauthorized files.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | fast-filesystem-mcp | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fast-filesystem-mcp. 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.
Remediation status
No patched version of fast-filesystem-mcp has shipped for GHSA-j893-m93w-jwjw yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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-j893-m93w-jwjw 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-j893-m93w-jwjw. 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-j893-m93w-jwjw in your dependencies?
O3 detects GHSA-j893-m93w-jwjw across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.