CVE-2026-126831

Cpio: cpio: stack-based buffer overflow in write_out_tar_header() with long usernames/groupnames

Published Nov 12, 2026 CVSS 3.1 · 5.5 Medium EPSS n/a KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Red Hat
Red Hat enterprise Linux
Redhat hardened Images
Vendors & Products Red Hat
Red Hat enterprise Linux
Redhat hardened Images
Type Values Removed Values Added
Description 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.
Title Cpio: cpio: stack-based buffer overflow in write_out_tar_header() with long usernames/groupnames
First Time appeared Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat rhel Els
Weaknesses CWE-121
CPEs cpe:/a:redhat:enterprise_linux:10
cpe:/a:redhat:enterprise_linux:8
cpe:/a:redhat:enterprise_linux:9
cpe:/a:redhat:hummingbird:1
cpe:/o:redhat:rhel_els:6
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat rhel Els
References
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 12, 2026, 5:27 PM
Reserved
Nov 11, 2026, 9:04 PM
Status
Awaiting Analysis
Published
Nov 12, 2026, 6:17 PM
Modified
Nov 12, 2026, 6:17 PM
Severity
Moderate
Public date
Nov 7, 2026, 12:00 AM