CVE-2026-33055 tar-rs incorrectly ignores PAX size headers if header size is nonzero
Attackers can craft tar archives that appear differently to tar-rs than other parsers, potentially bypassing security checks or causing logic errors.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-33055?
CVE-2026-33055 is a medium-severity vulnerability in alexcrichton tar-rs, published on 20 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
tar-rs is a tar archive reading/writing library for Rust. Versions 0.4.44 and below have conditional logic that skips the PAX size header in cases where the base header size is nonzero. As part of CVE-2025-62518, the astral-tokio-tar project was changed to correctly honor PAX size headers in the case where it was different from the base header. This is almost the inverse of the astral-tokio-tar issue. Any discrepancy in how tar parsers honor file size can be used to create archives that appear differently when unpacked by different archivers. In this case, the tar-rs (Rust tar) crate is an outlier in checking for the header size - other tar parsers (including e.g. Go archive/tar) unconditionally use the PAX size override. This can affect anything that uses the tar crate to parse archives and expects to have a consistent view with other parsers. This issue has been fixed in version 0.4.45.
Weakness: CWE-843
Which versions are affected by CVE-2026-33055?
3 open source packages ship an affected version, including tar. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
tar crates.io | All versions | 0.4.45 |
tar crates.io | All versions | 0.4.45 |
tar crates.io | From 0.0.0-0 | 0.4.45 |
Products include Alexcrichton Tar-Rs.
How do I fix CVE-2026-33055?
Upgrade tar to 0.4.45 or later.
Is CVE-2026-33055 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33055 exists.
Sources
Also known as AZL-80318, AZL-80496, AZL-80505, AZL-80508, AZL-80520, AZL-83034 and 10 more.