CVE-2021-31870

Publication date 30 April 2021

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

An issue was discovered in klibc before 2.0.9. Multiplication in the calloc() function may result in an integer overflow and a subsequent heap buffer overflow.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
klibc	22.04 LTS jammy	Not affected
	21.10 impish	Not affected
	21.04 hirsute	Ignored end of life
	20.10 groovy	Ignored end of life
	20.04 LTS focal	Fixed 2.0.7-1ubuntu5.1
	18.04 LTS bionic	Fixed 2.0.4-9ubuntu2.1
	16.04 LTS xenial	Fixed 2.0.4-8ubuntu1.16.04.4+esm1
	14.04 LTS trusty	Fixed 2.0.3-0ubuntu1.14.04.3+esm2

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Notes

mdeslaur

only used in initramfs, doesn't parse untrusted data

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
klibc	Upstream: ?id=292

Severity score breakdown

CVSS version: CVSS v3.0

Base score 9.8 · Critical

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	High
Integrity impact	High
Availability impact	High

Scores

Parameter	Value
Base score	9.8 · Critical
Exploitability score	-
Impact score	-