Cyber Posture

CVE-2026-9538

High
Microsoft: not affectedMSmacOS: not affectedMacLinux: not affectedLnxMobile: not affectedMobNetwork: not affectedNetApplication: affectedAppOther: not affectedOth

Published: 26 May 2026

Published
26 May 2026
Modified
27 May 2026
KEV Added
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Patch
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CVSS Score 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0002 4.3th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-9538 is a high-severity Memory Allocation with Excessive Size Value (CWE-789) vulnerability in Archive\ \. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 4.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

Threat & Defense at a Glance

What attackers do: exploitation maps to Application or System Exploitation (T1499.004).
Threat & Defense Details

MITRE ATT&CK Enterprise TechniquesAI

T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
Why these techniques?

Memory exhaustion via unbounded tar header size field directly enables application/system DoS through exploitation of input parsing.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

NVD Description

Archive::Tar versions before 3.10 for Perl allow memory exhaustion via attacker controlled entry size field in tar header. _read_tar() reads each entry's payload with $handle->read($$data, $block), where $block is derived from the entry's 12-byte size field in the tar header…

more

with no upper bound on that value. A crafted header declaring a multi-gigabyte size causes Perl to allocate a scalar of that size.

Deeper analysisAI

Automated synthesis unavailable for this CVE.

Details

CWE(s)
CWE-789

Affected Products

archive\
\
tar_project

EU & UK References

References