A GNU C Library security update has been released for Ubuntu Linux 22.04 LTS and 23.04.

[USN-6409-1] GNU C Library vulnerabilities

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Ubuntu Security Notice USN-6409-1
October 03, 2023

glibc vulnerabilities
==========================================================================

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

- Ubuntu 23.04
- Ubuntu 22.04 LTS

Summary:

Several security issues were fixed in GNU C Library.

Software Description:
- glibc: GNU C Library

Details:

It was discovered that the GNU C Library incorrectly handled the
GLIBC_TUNABLES environment variable. An attacker could possibly use this
issue to perform a privilege escalation attack. (CVE-2023-4911)

It was discovered that the GNU C Library incorrectly handled certain DNS
responses when the system was configured in no-aaaa mode. A remote attacker
could possibly use this issue to cause the GNU C Library to crash,
resulting in a denial of service. This issue only affected Ubuntu 23.04.
(CVE-2023-4527)

Update instructions:

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

Ubuntu 23.04:
libc6 2.37-0ubuntu2.1

Ubuntu 22.04 LTS:
libc6 2.35-0ubuntu3.4

After a standard system update you need to reboot your computer to make all
the necessary changes.

References:
https://ubuntu.com/security/notices/USN-6409-1
CVE-2023-4527, CVE-2023-4911

Package Information:
https://launchpad.net/ubuntu/+source/glibc/2.37-0ubuntu2.1
https://launchpad.net/ubuntu/+source/glibc/2.35-0ubuntu3.4