Published Nov 12, 2026Sources checked Nov 13, 2026
5.5MEDIUMCVSS out of 10
What this means
Review the available evidence
CVE-2026-126831 and is rated Medium severity with a CVSS score of 5.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
What to do next
Remediation and response
Microsoft Security Response Center guidance
Vendor revision: Nov 13, 2026
Release Notes
CISA KEVNot listedBased on the latest collected catalog
EPSSUnavailableNo current score collected
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-126831?
A flaw was found in cpio. A local user can cause a Denial of Service (DoS) by triggering a stack-based buffer overflow when creating archives in tar or ustar formats.
When archiving files owned by users or groups with names exceeding 32 characters, cpio copies these names into fixed-size memory without verifying their length. This unbounded copy corrupts stack memory and causes the application to crash.