CVE-2021-23177

Publication date 24 December 2021

Last updated 18 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

An improper link resolution flaw while extracting an archive can lead to changing the access control list (ACL) of the target of the link. An attacker may provide a malicious archive to a victim user, who would trigger this flaw when trying to extract the archive. A local attacker may use this flaw to change the ACL of a file on the system and gain more privileges.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libarchive	25.10 questing	Not affected
	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Fixed 3.4.3-2ubuntu0.1
	21.04 hirsute	Ignored end of life
	20.04 LTS focal	Fixed 3.4.0-2ubuntu1.1
	18.04 LTS bionic	Vulnerable
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Needs evaluation

Notes

mdeslaur

intrusive backport to bionic

Patch details

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

Package	Patch details
libarchive	Upstream: fba4f12

Severity score breakdown

Parameter	Value
Base score	7.8 · High
Attack vector	Local
Attack complexity	Low
Privileges required	None
User interaction	Required
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H