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Public proof of conceptFix available

CVE-2026-33055

A public proof of concept exists; no exploitation attested.

  • Published2026-03-20
  • Fixed in0.4.45
  • WeaknessCWE-843

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2026-03-2007:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-33055?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-33055?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Alexcrichton tar-rs
BranchAffectedFixed in
0.4< 0.4.450.4.45
0.x≥ 0.0.0-0, < 0.4.450.4.45

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Alexcrichton tar-rs to 0.4.45

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CISA-ADPSSVC decisionpoc2026-03-20
  • OpenCVESSVC decisionpoc—
  • CNACVSS 4.05.1read 2026-10-23
  • NVDCVSS 3.18.1read 2026-10-23
  • CNAweakness (CWE)CWE-843read 2026-10-23
  • FIRST EPSSEPSS score0.5 %2026-10-23
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
CVSS 4.0 vector
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
Published
2026-03-20
Last Modified
2026-06-17
NVD status
Analyzed

Frequently asked questions

What is CVE-2026-33055?

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.

Is CVE-2026-33055 actively exploited?

A proof-of-concept exploit exists for CVE-2026-33055, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-33055?

CVE-2026-33055 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.

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