CVE-2026-33055
Published: 20 March 2026
Summary
CVE-2026-33055 is a medium-severity Type Confusion (CWE-843) vulnerability in Alexcrichton Tar-Rs. Its CVSS base score is 5.1 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Malicious File (T1204.002); ranked at the 31.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 RA-5 (Vulnerability Monitoring and Scanning) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-33055 is a vulnerability in the tar-rs Rust library for reading and writing tar archives, affecting versions 0.4.44 and below. The issue arises from conditional logic that skips the PAX size header when the base header size is nonzero, making tar-rs an outlier compared to other tar parsers, such as Go's archive/tar, which unconditionally honor PAX size overrides. This leads to discrepancies where crafted tar archives unpack differently depending on the parser used, impacting any application or system relying on the tar-rs crate for consistent tar archive processing.
Attackers can exploit this vulnerability remotely with low attack complexity and no required privileges, though user interaction is necessary, such as tricking a victim into unpacking a malicious archive. Exploitation leverages the parsing inconsistency to achieve high confidentiality and integrity impacts (CVSS 8.1: AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N), potentially allowing unauthorized data access or modification in environments expecting uniform behavior across tar tools. The root cause aligns with CWE-843 (Access of Resource Using Incompatible Type).
The vulnerability has been fixed in tar-rs version 0.4.45. Official advisories recommend updating to this version or later to ensure consistent PAX header handling. Details, including the fixing commit and security advisory, are available at the tar-rs GitHub repository, with a related inverse issue documented in CVE-2025-62518.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-13596
Vulnerability details
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The CVE description explicitly states exploitation requires tricking a victim into unpacking a crafted malicious tar archive (UI:R), directly mapping to user execution of a malicious file that leverages the PAX header parsing inconsistency for C/I impacts.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates the vulnerability by requiring timely remediation through updating tar-rs to version 0.4.45 or later, eliminating the PAX header skipping logic.
Enables identification of vulnerable tar-rs versions (0.4.44 and below) through vulnerability scanning, allowing proactive patching before exploitation via malicious archives.
Maintains an inventory of system components including third-party libraries like tar-rs, facilitating tracking of vulnerable versions and targeted remediation.