CVE-2026-59874: node-tar: Negative tar entry size causes infinite loop in archive replace

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-07-08 · updated 2026-10-25
Weakness: CWE-835

Description

node-tar is a tar archive manipulation library for Node.js. Prior to 7.5.18, tar.replace accepts a checksum-valid tar header with a negative base-256 encoded entry size, causing the archive scanner to make no progress while repeatedly parsing the same header. This issue is fixed in version 7.5.18.

Affected products

isaacs node-tar: before 7.5.18 — fixed in 7.5.18
Npm Tar: before 7.5.18 — fixed in 7.5.18

How to fix

Upgrade to a fixed version: isaacs node-tar 7.5.18; Npm Tar 7.5.18. Check the vendor advisory for mitigations.

References

https://github.com/isaacs/node-tar/commit/9e78bf058b2c22dd4d52e00d8922d5c06fc2f7b5
https://github.com/isaacs/node-tar/releases/tag/v7.5.18
https://github.com/isaacs/node-tar/security/advisories/GHSA-8x88-c5mf-7j5w
https://github.com/isaacs/node-tar/security/advisories/GHSA-8x88-c5mf-7j5w

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