GHSA-qq89-hq3f-393p
HIGHArbitrary File Creation/Overwrite via insufficient symlink protection due to directory cache poisoning using symbolic links
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.
tarnpmDescription
Impact
Arbitrary File Creation, Arbitrary File Overwrite, Arbitrary Code Execution
node-tar aims to guarantee that any file whose location would be modified by a symbolic link is not extracted. This is, in part, achieved by ensuring that extracted directories are not symlinks. Additionally, in order to prevent unnecessary stat calls to determine whether a given path is a directory, paths are cached when directories are created.
This logic was insufficient when extracting tar files that contained two directories and a symlink with names containing unicode values that normalized to the same value. Additionally, on Windows systems, long path portions would resolve to the same file system entities as their 8.3 "short path" counterparts. A specially crafted tar archive could thus include directories with two forms of the path that resolve to the same file system entity, followed by a symbolic link with a name in the first form, lastly followed by a file using the second form. It led to bypassing node-tar symlink checks on directories, essentially allowing an untrusted tar file to symlink into an arbitrary location and subsequently extracting arbitrary files into that location, thus allowing arbitrary file creation and overwrite.
The v3 branch of node-tar has been deprecated and did not receive patches for these issues. If you are still using a v3 release we recommend you update to a more recent version of node-tar. If this is not possible, a workaround is available below.
Patches
6.1.9 || 5.0.10 || 4.4.18
Workarounds
Users may work around this vulnerability without upgrading by creating a custom filter method which prevents the extraction of symbolic links.
const tar = require('tar')
tar.x({
file: 'archive.tgz',
filter: (file, entry) => {
if (entry.type === 'SymbolicLink') {
return false
} else {
return true
}
}
})
Users are encouraged to upgrade to the latest patched versions, rather than attempt to sanitize tar input themselves.
Fix
The problem is addressed in the following ways, when comparing paths in the directory cache and path reservation systems:
- The
String.normalize('NFKD')method is used to first normalize all unicode to its maximally compatible and multi-code-point form. - All slashes are normalized to
/on Windows systems (on posix systems,\is a valid filename character, and thus left intact). - When a symbolic link is encountered on Windows systems, the entire directory cache is cleared. Collisions related to use of 8.3 short names to replace directories with other (non-symlink) types of entries may make archives fail to extract properly, but will not result in arbitrary file writes.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | tar | ≥ 3.0.0&&< 4.4.18 | 4.4.18 |
| 📦npm | tar | ≥ 5.0.0&&< 5.0.10 | 5.0.10 |
| 📦npm | tar | ≥ 6.0.0&&< 6.1.9 | 6.1.9 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tar. 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 to 4.4.18 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qq89-hq3f-393p 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-qq89-hq3f-393p 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-qq89-hq3f-393p. 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-qq89-hq3f-393p in your dependencies?
O3 detects GHSA-qq89-hq3f-393p across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.