CVE-2021-36084

Publication date 1 July 2021

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

The CIL compiler in SELinux 3.2 has a use-after-free in __cil_verify_classperms (called from __cil_verify_classpermission and __cil_pre_verify_helper).

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libsepol	22.04 LTS jammy	Not affected
	21.10 impish	Fixed 3.1-1ubuntu2.1
	21.04 hirsute	Ignored end of life
	20.10 groovy	Ignored end of life
	20.04 LTS focal	Fixed 3.0-1ubuntu0.1
	18.04 LTS bionic	Fixed 2.7-1ubuntu0.1
	16.04 LTS xenial	Fixed 2.4-2ubuntu0.1~esm1
	14.04 LTS trusty	Not affected

Get expanded security coverage with Ubuntu Pro

Reduce your average CVE exposure time from 98 days to 1 day with expanded CVE patching, ten-years security maintenance and optional support for the full stack of open-source applications. Free for personal use.

Get Ubuntu Pro 30-day free trial

Notes

sbeattie

AppArmor is the default LSM in Ubuntu, issue only affects compilation of selinux policy trusty version predates the introduction of CIL

Patch details

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

Package	Patch details
libsepol	Upstream: f34d3d3

Severity score breakdown

Parameter	Value
Base score	3.3 · Low
Attack vector	Local
Attack complexity	Low
Privileges required	None
User interaction	Required
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	Low
Vector	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

References

Related Ubuntu Security Notices (USN)

USN-5391-1
libsepol vulnerabilities
27 April 2022