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Fencer Vulns
critical 9.8

CVE-2021-31872 json

An issue was discovered in klibc before 2.0.9.

published 2021-04-30 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-18747

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.1%
EPSS 2.1% chance of exploitation in 30 days, percentile 81%
public exploits
0
none known

Summary

An issue was discovered in klibc before 2.0.9. Multiple possible integer overflows in the cpio command on 32-bit systems may result in a buffer overflow or other security impact.

Patch / fix

  • klibc_project klibc 2.0.9
  • klibc Debian 14, Debian 13, Debian 12 2.0.8-6

debian advisories DEBIAN-CVE-2021-31872

  • klibc Ubuntu 18.04 LTS 2.0.4-9ubuntu2.1
  • klibc Ubuntu 20.04 LTS 2.0.7-1ubuntu5.1
  • klibc Ubuntu Pro 14.04 LTS 2.0.3-0ubuntu1.14.04.3+esm2
  • klibc Ubuntu Pro 16.04 LTS 2.0.4-8ubuntu1.16.04.4+esm1

ubuntu advisories UBUNTU-CVE-2021-31872

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • klibc Alpine 3.24, Alpine 3.23, Alpine 3.22 +3 more 2.0.9-r0

alpine advisories ALPINE-CVE-2021-31872

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Exploit prediction

2.08% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.