# CVE-2026-53655: isaacs node-tar interpretation conflict in PAX header parsing

Source: https://junglewise.ai/threats/cve-2026-53655-isaacs-node-tar-interpretation-conflict-in-pax-header-parsing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-22. Updated: 2026-06-22  
License: CC BY 4.0 with a link back

CVE-2026-53655 · Severity: medium · CVSS 4 · Published 2026-06-22

The node-tar library, a widely used tool for handling tar archives in the Node.js ecosystem, contains a vulnerability that allows for 'file smuggling.' By crafting a malicious archive, an attacker can cause node-tar to see a different set of files than other standard tools. This can be used to bypass security scanners, where a malicious file is hidden from a scanner but still extracted and executed by the final system.

Technologies: [tar (npm)](https://junglewise.ai/threats/technologies/npm-tar). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-53655 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-53655 being exploited in the wild.

**How severe is CVE-2026-53655?** Medium severity, with a CVSS score of 4, published 22 June 2026.

**Which products and versions are affected?** tar (npm) SEMVER:introduced=0,fixed=7.5.16.

**Is there a fix for CVE-2026-53655?** Yes. tar (npm): upgrade to 7.5.16 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-53655 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-53655?** 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 7.5.16 or later

  ```sh
  npm install tar@7.5.16
  ```


## Technical details

A vulnerability exists in node-tar prior to version 7.5.16 where the parser applies PAX extended header overrides (such as 'size') to the immediate next header regardless of its type. According to POSIX pax standards, these overrides should only apply to the next file entry, not intermediary metadata headers like GNU long-name (L) or long-link (K) entries. By setting a PAX size override before a metadata header, an attacker can desynchronize node-tar's stream cursor. This results in a 'parser interpretation differential' (CWE-436) where node-tar and other mainstream parsers (like GNU tar or libarchive) disagree on the archive's contents, allowing files to be hidden from security tooling that relies on node-tar for inspection.

## Affected products

- isaacs tar (node-tar) < 7.5.16

## Identifiers

- CVE-2026-53655
- GHSA-vmf3-w455-68vh

## Timeline

- 2026-06-01: advisory: GitHub Security Advisory published
- 2026-06-22: disclosed: CVE-2026-53655 published to NVD
- 2026-06-22: patched: Fixed in version 7.5.16

## References

- [https://github.com/isaacs/node-tar/security/advisories/GHSA-vmf3-w455-68vh](https://github.com/isaacs/node-tar/security/advisories/GHSA-vmf3-w455-68vh)

## Related threats

- [npm tar stack overflow in mapHas filter with long paths](https://junglewise.ai/threats/cve-2026-73566-npm-tar-stack-overflow-in-maphas-filter-with-long-paths)
- [node-tar denial of service via NUL byte in PAX records](https://junglewise.ai/threats/cve-2026-59875-node-tar-denial-of-service-via-nul-byte-in-pax-records)
- [isaacs node-tar infinite loop in tar.replace](https://junglewise.ai/threats/cve-2026-59874-isaacs-node-tar-infinite-loop-in-tar-replace)
- [isaacs node-tar Denial of Service via Gzip Bomb](https://junglewise.ai/threats/cve-2026-59873-isaacs-node-tar-denial-of-service-via-gzip-bomb)
- [isaacs node-tar denial of service via PAX numeric path type confusion](https://junglewise.ai/threats/cve-2026-59871-isaacs-node-tar-denial-of-service-via-pax-numeric-path-type)