CVE-2026-53600 async-tar PAX extension-header desync enables tar entry/content smuggling
An attacker can craft a tar archive to desync the parser, causing content smuggling and incorrect file extraction in async-tar.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-53600?
CVE-2026-53600 is a medium-severity vulnerability in dignifiedquire async-tar, published on 2 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
async-tar is a tar archive reading/writing library for async Rust. Prior to version 0.6.1, async-tar mis-applies a buffered PAX size extension to an intermediary extension header (a GNU longname L, a GNU longlink K, or a PAX x/g header) instead of to the next file entry. POSIX requires a PAX extended-header record set to describe the next file entry, never an intervening extension header. Because poll_next_raw (src/archive.rs) threads the buffered PAX records into the size computation of whatever raw header it reads next — and that header can be an intermediary L — the stream cursor is advanced by an attacker-chosen amount when the L body is consumed. The parser then desyncs relative to a POSIX-correct tar parser (e.g. GNU tar), reading subsequent bytes at the wrong block boundary. This issue has been patched in version 0.6.1.
Which versions are affected by CVE-2026-53600?
2 open source packages ship an affected version, including async-tar.
| Package | Affected | Fixed in |
|---|---|---|
async-tar crates.io | All versions | 0.6.1 |
async-tar crates.io | All versions | 0.6.1 |
How do I fix CVE-2026-53600?
Upgrade async-tar to 0.6.1 or later.
Is CVE-2026-53600 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53600 exists.
Sources
Also known as DEBIAN-CVE-2026-53600, GHSA-35rm-7j9c-2f7m, UBUNTU-CVE-2026-53600.