Is CVE-2026-59871 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-59871 being exploited in the wild.

How severe is CVE-2026-59871?

Medium severity, with a CVSS score of 5.3, published 8 July 2026.

Which products and versions are affected?

tar (npm) SEMVER:introduced=0,fixed=7.5.18.

Is there a fix for CVE-2026-59871?

Yes. tar (npm): upgrade to 7.5.18 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-59871 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-59871?

Check whether you run tar (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-59871: isaacs node-tar denial of service via PAX numeric path type confusion

CVE-2026-59871 · Severity: medium · CVSS 5.3 · Published 2026-07-08

A vulnerability in the node-tar library, a popular tool for handling compressed archives in Node.js, allows a small, specially crafted file to crash any application that attempts to extract it. This can lead to a complete service outage for tools like npm, CI/CD pipelines, and file upload services. The crash is difficult to prevent because it bypasses standard error-handling mechanisms.

Technologies: tar (npm). Vendors: npm.

Quick answers

Is CVE-2026-59871 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-59871 being exploited in the wild.
How severe is CVE-2026-59871?: Medium severity, with a CVSS score of 5.3, published 8 July 2026.
Which products and versions are affected?: tar (npm) SEMVER:introduced=0,fixed=7.5.18.
Is there a fix for CVE-2026-59871?: Yes. tar (npm): upgrade to 7.5.18 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-59871 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-59871?: Check whether you run tar (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

tar (npm): upgrade to 7.5.18 or later
```
npm install tar@7.5.18
```

Technical details

The vulnerability is an incorrect type conversion (CWE-704) in the PAX header parser within `pax.ts`. The `parseKV` function uses a regular expression `/^[0-9]+$/` to identify numeric values and coerces them to JavaScript numbers using the unary plus operator. When a PAX header contains an all-digit `path` or `linkpath`, the resulting numeric value is passed to `Unpack.CHECKPATH`, which calls `.split('/')`. Because numbers do not possess the `.split` method, a synchronous `TypeError` is thrown. This error propagates as an `uncaughtException`, bypassing standard `'error'` or `'warn'` event handlers and the `strict: false` configuration. The issue is patched in version 7.5.18.

Affected products

isaacs (node-tar) tar <= 7.5.17

Identifiers

CVE-2026-59871
GHSA-w8wr-v893-vjvp

Timeline

2026-06-27: disclosed
2026-06-27: patched: Fixed in version 7.5.18
2026-07-20: advisory

References

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