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Fencer Vulns
high 8.1

CVE-2026-33055 json

tar-rs incorrectly ignores PAX size headers if header size is nonzero

published 2026-03-19 7 mo ago modified 2026-09-10 1 mo ago also EUVD-2026-13596 , GHSA-gchp-q4r4-x4ff , RUSTSEC-2026-0068

cvss
8.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits
0
none known

Summary

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.

Patch / fix

  • crates.io tar 0.4.45
  • alexcrichton tar-rs 0.4.45
  • alexcrichton tar 0.4.45
  • rustc Debian 13 1.85.1+dfsg1-1+deb13u1
  • rustc Debian 14 1.92.0+dfsg1-2
  • rust-tar Debian 14 0.4.45-1

debian advisories DEBIAN-CVE-2026-33055

  • rpm-ostree Azure Linux 3.0 2024.4-10
  • rust Azure Linux 3.0 1.75.0-28
  • rust Azure Linux 3.0 1.90.0-7
  • trident Azure Linux 3.0 0.22.0-1
  • clamav Azure Linux 3.0 1.5.2-2

azure linux advisories AZL-80496AZL-80505AZL-80508AZL-80520AZL-83034

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/alexcrichton/tar-rs/security/advisories/GHSA-gchp-q4r4-x4ff referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
CNA 4.0 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/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
NVD 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
crates.io tar
<0.4.45
>=0.0.0-0, <0.4.45
0.4.45

Affected products

  • alexcrichton tar-rs

Classification

Weakness
  • CWE-843 Access of Resource Using Incompatible Type

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.