How severe is CVE-2021-37713?

CVE-2021-37713 has a CVSS score of 8.6/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-37713?

CVE-2021-37713 affects the following packages: tar (npm), tar (npm), tar (npm). Ecosystems affected: npm.

How do I fix CVE-2021-37713?

Update tar to 4.4.18 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-37713 is resolved across your whole dependency graph.

How do I detect CVE-2021-37713 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tar, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-37713 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2021-37713 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-37713 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-37713?

CVE-2021-37713 has an EPSS (Exploit Prediction Scoring System) score of 1.3%, placing it in the 69th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-37713?

CVE-2021-37713 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2021-37713 published, and has it been updated?

CVE-2021-37713 was published on August 31, 2021 and was last updated on August 27, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

HIGH severity

CVE-2021-37713 — tar

HIGHFix: isaacs/node-tar@52b09e3

CVE-2021-37713 is a high-severity (CVSS 8.6) Path Traversal vulnerability in tar. A fix is available for tar — see the affected versions and patch details below.

Arbitrary File Creation/Overwrite on Windows via insufficient relative path sanitization

Also known asGHSA-5955-9wpr-37jh

Published

Aug 31, 2021

Updated

Aug 27, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Oct 12, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.3%probability of exploitation in next 30 days

Lower Risk+0.01%

Lower risk than most CVEs69th percentile — riskier than 69% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-37713 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

3 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

8Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

tarnpm

90.6Mdownloads / week

Description

Impact

Arbitrary File Creation, Arbitrary File Overwrite, Arbitrary Code Execution

node-tar aims to guarantee that any file whose location would be outside of the extraction target directory is not extracted. This is, in part, accomplished by sanitizing absolute paths of entries within the archive, skipping archive entries that contain .. path portions, and resolving the sanitized paths against the extraction target directory.

This logic was insufficient on Windows systems when extracting tar files that contained a path that was not an absolute path, but specified a drive letter different from the extraction target, such as C:some\path. If the drive letter does not match the extraction target, for example D:\extraction\dir, then the result of path.resolve(extractionDirectory, entryPath) would resolve against the current working directory on the C: drive, rather than the extraction target directory.

Additionally, a .. portion of the path could occur immediately after the drive letter, such as C:../foo, and was not properly sanitized by the logic that checked for .. within the normalized and split portions of the path.

This only affects users of node-tar on Windows systems.

Patches

4.4.18 || 5.0.10 || 6.1.9

Workarounds

There is no reasonable way to work around this issue without performing the same path normalization procedures that node-tar now does.

Users are encouraged to upgrade to the latest patched versions of node-tar, rather than attempt to sanitize paths themselves.

Fix

The fixed versions strip path roots from all paths prior to being resolved against the extraction target folder, even if such paths are not "absolute".

Additionally, a path starting with a drive letter and then two dots, like c:../, would bypass the check for .. path portions. This is checked properly in the patched versions.

Finally, a defense in depth check is added, such that if the entry.absolute is outside of the extraction taret, and we are not in preservePaths:true mode, a warning is raised on that entry, and it is skipped. Currently, it is believed that this check is redundant, but it did catch some oversights in development.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`tar`	all versions	4.4.18`npm install tar@4.4.18`
📦npm	`tar`	≥ 5.0.0&&< 5.0.10	5.0.10`npm install tar@5.0.10`
📦npm	`tar`	≥ 6.0.0&&< 6.1.9	6.1.9`npm install tar@6.1.9`

Affected Products

3 products · 6 configurations

Application

tarnpmjs

≥ 6.0.0 && < 6.1.9

range

Application

graalvmoracle

2 versions

20.3.321.2.0

Application

sinec infrastructure network servicessiemens

< 1.0.1.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tar, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update tar to 4.4.18 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-37713 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

### Impact Arbitrary File Creation, Arbitrary File Overwrite, Arbitrary Code Execution node-tar aims to guarantee that any file whose location would be outside of the extraction target directory is not extracted. This is, in part, accomplished by sanitizing absolute paths of entries within the archive, skipping archive entries that contain `..` path portions, and resolving the sanitized paths against the extraction target directory. This logic was insufficient on Windows systems when extracting tar files that contained a path that was not an absolute path, but specified a drive letter diffe