What’s Vulnerable › Vulnerabilities

CVE-2018-20834: Arbitrary File Overwrite in tar

• Severity: high (CVSS 7.5 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.1% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2019-04-30 · updated 2026-06-17
• Weakness: CWE-59

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).

Affected products

• isaacs node-tar: before 2.2.2; from 3.0.0 before 4.4.2 — fixed in 2.2.2, 4.4.2
• Npm Tar: from 3.0.0 before 4.4.2; before 2.2.2 — fixed in 4.4.2, 2.2.2

How to fix

Upgrade to a fixed version: isaacs node-tar 2.2.2, 4.4.2; Npm Tar 4.4.2, 2.2.2. Check the vendor advisory for mitigations.

References

• https://access.redhat.com/errata/RHSA-2019:1821
• https://github.com/npm/node-tar/commit/7ecef07da6a9e72cc0c4d0c9c6a8e85b6b52395d
• https://github.com/npm/node-tar/commit/b0c58433c22f5e7fe8b1c76373f27e3f81dcd4c8
• https://github.com/npm/node-tar/commits/v2.2.2
• https://github.com/npm/node-tar/compare/58a8d43...a5f7779
• https://hackerone.com/reports/344595
• 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
• https://github.com/npm/node-tar/commits/v2.2.2
• https://github.com/npm/node-tar/compare/58a8d43...a5f7779

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