=========================================================================Ubuntu Security Notice USN-5391-1
April 27, 2022

libsepol vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 21.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 ESM

Summary:

Several security issues were fixed in libsepol.

Software Description:
- libsepol: SELinux library for manipulating binary security policies

Details:

Nicolas Iooss discovered that libsepol incorrectly handled memory
when handling policies. An attacker could possibly use this issue
to cause a crash, resulting in a denial of service, or possibly
execute arbitrary code. (CVE-2021-36084)

It was discovered that libsepol incorrectly handled memory when
handling policies. An attacker could possibly use this issue to cause
a crash, resulting in a denial of service, or possibly execute
arbitrary code. (CVE-2021-36085)

It was discovered that libsepol incorrectly handled memory when
handling policies. An attacker could possibly use this issue to cause
a crash, resulting in a denial of service, or possibly execute
arbitrary code. This issue only affects Ubuntu 18.04 LTS,
Ubuntu 20.04 LTS and Ubuntu 21.10. (CVE-2021-36086)

It was discovered that libsepol incorrectly validated certain data,
leading to a heap overflow. An attacker could possibly use this issue
to cause a crash, resulting in a denial of service, or possibly execute
arbitrary code. (CVE-2021-36087)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 21.10:
   libsepol1                       3.1-1ubuntu2.1
   sepol-utils                     3.1-1ubuntu2.1

Ubuntu 20.04 LTS:
   libsepol1                       3.0-1ubuntu0.1
   sepol-utils                     3.0-1ubuntu0.1

Ubuntu 18.04 LTS:
   libsepol1                       2.7-1ubuntu0.1
   sepol-utils                     2.7-1ubuntu0.1

Ubuntu 16.04 ESM:
   libsepol1                       2.4-2ubuntu0.1~esm1
   sepol-utils                     2.4-2ubuntu0.1~esm1

In general, a standard system update will make all the necessary changes.

References:
   https://ubuntu.com/security/notices/USN-5391-1
   CVE-2021-36084, CVE-2021-36085, CVE-2021-36086, CVE-2021-36087

Package Information:
   https://launchpad.net/ubuntu/+source/libsepol/3.1-1ubuntu2.1
   https://launchpad.net/ubuntu/+source/libsepol/3.0-1ubuntu0.1
   https://launchpad.net/ubuntu/+source/libsepol/2.7-1ubuntu0.1