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Vulnerability record · CVE-2018-20834 · published 30 April 2019

CVE-2018-20834: Isaacs tar link following vulnerability

Isaacs · Tar

A vulnerability was found in node-tar before version 4.4.2 (excluding version 2.2.2). An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content. A patch has been applied to node-tar v2.2.2).

7.5 CVSS 3.0 High EPSS 3.1% · top 12.6% CWE-59 · Link following
7.5CVSS 3.0 base score, v2 6.4
3.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
14References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

A vulnerability was found in node-tar before version 4.4.2 (excluding version 2.2.2). An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content. A patch has been applied to node-tar v2.2.2).

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://access.redhat.com/errata/RHSA-2019:1821
https://github.com/npm/node-tar/commit/7ecef07da6a9e72cc0c4d0c9c6a8e85b6b52395d
https://github.com/npm/node-tar/commit/b0c58433c22f5e7fe8b1c76373f27e3f81dcd4c8 PatchThird Party Advisory
https://github.com/npm/node-tar/commits/v2.2.2
https://github.com/npm/node-tar/compare/58a8d43...a5f7779 PatchThird Party Advisory
https://hackerone.com/reports/344595 ExploitThird Party Advisory
https://nvd.nist.gov/vuln/detail/CVE-2018-20834
https://access.redhat.com/errata/RHSA-2019:1821
https://github.com/npm/node-tar/commit/7ecef07da6a9e72cc0c4d0c9c6a8e85b6b52395d
https://github.com/npm/node-tar/commit/b0c58433c22f5e7fe8b1c76373f27e3f81dcd4c8 PatchThird Party Advisory
https://github.com/npm/node-tar/commits/v2.2.2
https://github.com/npm/node-tar/compare/58a8d43...a5f7779 PatchThird Party Advisory
https://hackerone.com/reports/344595 ExploitThird Party Advisory
https://nvd.nist.gov/vuln/detail/CVE-2018-20834

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2018-20834), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.