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CVE-2021-31872

31
FAUCET Score

CVE-2021-31872 is a critical vulnerability affecting klibc versions prior to 2.0.9, specifically impacting the cpio command on 32-bit systems. This flaw involves multiple potential integer overflows that could lead to buffer overflows, resulting in severe security consequences. With a CVSS score of 9.8, it is highly severe, allowing unauthenticated remote attackers to achieve high confidentiality, integrity, and availability impacts with low attack complexity. Currently, there is no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.0.9CPE matchmatch criteria
cpe:2.3:a:klibc_project:klibc:*:*:*:*:*:x86:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.06%
Probability of exploitation in next 30 days
EPSS Percentile
79.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0206 is in the 68th percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

git.kernel.org / pub/scm/libs/klibc/klibc.git/commit
PatchThird Party Advisory
kernel.org / pub/linux/libs/klibc/2.0
Release NotesThird Party Advisory
lists.debian.org / debian-lts-announce/2021/06/msg00025.html
Third Party Advisory
lists.zytor.com / archives/klibc/2021-April/004593.html
Mailing ListRelease NotesThird Party Advisory
openwall.com / lists/oss-security/2021/04/30/1
Mailing ListRelease NotesThird Party Advisory