CVE-2026-126831
Cpio: cpio: stack-based buffer overflow in write_out_tar_header() with long usernames/groupnames
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.
INFO
Published Date :
Nov. 12, 2026, 6:17 p.m.
Last Modified :
Nov. 12, 2026, 6:17 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-126831
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 53f830b8-0a3f-465b-8143-3b8a9948e749 | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update the cpio utility to the latest version.
- Apply vendor patches for cpio.
- Avoid creating archives with excessively long names.
- Review file ownership and group names.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-126831.
| URL | Resource |
|---|---|
| https://access.redhat.com/security/cve/CVE-2026-126831 | |
| https://bugzilla.redhat.com/show_bug.cgi?id=2571893 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-126831 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-126831
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-126831 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-126831 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Nov. 12, 2026
Action Type Old Value New Value 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. Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-121 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/126xxx/CVE-2026-126831.json">CVE-2026-126831</a> Added Reference https://access.redhat.com/security/cve/CVE-2026-126831 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2571893