CVE-2026-53655 node-tar applies PAX size override to intermediary GNU long-name/long-link headers, causing tar parser interpretation differential (file smuggling)
Attackers can craft archives that bypass security scanners by exploiting parser differences in node-tar, hiding malicious files from inspection tools.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-53655?
CVE-2026-53655 is a medium-severity vulnerability in isaacs node-tar, published on 22 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-436
Which versions are affected by CVE-2026-53655?
2 open source packages ship an affected version, including tar. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
tar npm | All versions | 7.5.16 |
tar npm | All versions | 7.5.16 |
Products include Isaacs Tar.
How do I fix CVE-2026-53655?
Upgrade tar to 7.5.16 or later.
Is CVE-2026-53655 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53655 exists.
Other vulnerabilities in isaacs node-tar
- CVE-2026-59873 node-tar: Decompression/parse DoS via unlimited input
- CVE-2026-23950 node-tar has Race Condition in Path Reservations via Unicode Ligature Collisions on macOS APFS
- CVE-2026-59874 node-tar: Negative tar entry size causes infinite loop in archive replace
- CVE-2026-31802 node-tar Symlink Path Traversal via Drive-Relative Linkpath
- CVE-2026-29786 node-tar: Hardlink Path Traversal via Drive-Relative Linkpath
Sources
Also known as CLEANSTART-2026-AO11552, CLEANSTART-2026-EK83190, CLEANSTART-2026-KF01846, CLSA-2026-1782089813, DEBIAN-CVE-2026-53655, ECHO-28bc-03c1-ad35 and 35 more.