CVE-2026-53655: node-tar is a full-featured Tar for Node.js. Prior to 7.5.16, tar (node-tar) applies a PAX extended header's size= record (and other PAX overrides) to...

Description

node-tar is a full-featured Tar for Node.js. Prior to 7.5.16, tar (node-tar) applies a PAX extended header's size= record (and other PAX overrides) to the next header entry of any type, including intermediary metadata headers such as a GNU long-name (L) or long-link (K) entry. Per POSIX pax, a PAX extended header (x) describes the next file entry, not the intermediary extension headers that may sit between the x header and the file it annotates. Because node-tar lets the PAX size override the byte length of an intervening L/K/x header, an attacker can desynchronize node-tar's stream cursor relative to every other mainstream tar implementation (GNU tar, libarchive/bsdtar, Python tarfile, and the now-fixed tar-rs / astral-tokio-tar). The result is a tar parser interpretation differential (CWE-436): a single crafted archive yields a different set of members under node-tar than under the reference tar tools. An attacker can use this to hide a member from one parser while it is visible to another, which defeats security tooling whose scanner and extractor disagree on archive contents (e.g. a malware/secret scanner that lists entries with one library while a downstream step extracts with another) This vulnerability is fixed in 7.5.16.

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

CVSS 4.0

6.9/10

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.12%

1.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-436

Affected Software

Vendor	Product	Versions
Isaacs	Tar	< 7.5.16

References

https://github.com/isaacs/node-tar/security/advisories/GHSA-vmf3-w455-68vhExploit, Mitigation, Vendor Advisory
https://github.com/isaacs/node-tar/security/advisories/GHSA-vmf3-w455-68vhExploit, Mitigation, Vendor Advisory

Timeline

Published: Jun 22, 2026
Last Modified: Jun 26, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-53655?

node-tar is a full-featured Tar for Node.js. Prior to 7.5.16, tar (node-tar) applies a PAX extended header's size= record (and other PAX overrides) to the next header entry of any type, including intermediary metadata headers such as a GNU long-name (L) or long-link (K) entry. Per POSIX pax, a PAX extended header (x) describes the next file entry, not the intermediary extension headers that may sit between the x header and the file it annotates. Because node-tar lets the PAX size override the byte length of an intervening L/K/x header, an attacker can desynchronize node-tar's stream cursor relative to every other mainstream tar implementation (GNU tar, libarchive/bsdtar, Python tarfile, and the now-fixed tar-rs / astral-tokio-tar). The result is a tar parser interpretation differential (CWE-436): a single crafted archive yields a different set of members under node-tar than under the reference tar tools. An attacker can use this to hide a member from one parser while it is visible to another, which defeats security tooling whose scanner and extractor disagree on archive contents (e.g. a malware/secret scanner that lists entries with one library while a downstream step extracts with another) This vulnerability is fixed in 7.5.16.

How severe is CVE-2026-53655?

CVE-2026-53655 has a CVSS score of 6.9/10 (MEDIUM severity). The EPSS model estimates a 0.12% probability of exploitation in the next 30 days.

How do I fix CVE-2026-53655?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.