A GCC security update has been released for Ubuntu Linux 16.04 ESM.

==========================================================================
Ubuntu Security Notice USN-5770-1
December 08, 2022

gcc-5, gccgo-6 vulnerability
==========================================================================

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

- Ubuntu 16.04 ESM

Summary:

GNU Compiler Collection's (GCC) random number generation could be
made less random with specially crafted input.

Software Description:
- gcc-5: GNU C compiler
- gccgo-6: GNU Go compiler

Details:

Todd Eisenberger discovered that certain versions of GNU Compiler
Collection (GCC) could be made to clobber the status flag of RDRAND
and RDSEED with specially crafted input. This could potentially lead
to less randomness in random number generation.

Update instructions:

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

Ubuntu 16.04 ESM:
g++-5 5.4.0-6ubuntu1~16.04.12+esm2
gcc-5 5.4.0-6ubuntu1~16.04.12+esm2
gccgo-5 5.4.0-6ubuntu1~16.04.12+esm2
gccgo-6 6.0.1-0ubuntu1+esm1
gcj-5 5.4.0-6ubuntu1~16.04.12+esm2
gcj-5-jdk 5.4.0-6ubuntu1~16.04.12+esm2
gcj-5-jre-headless 5.4.0-6ubuntu1~16.04.12+esm2
gdc-5 5.4.0-6ubuntu1~16.04.12+esm2
gfortran-5 5.4.0-6ubuntu1~16.04.12+esm2
gnat-5 5.4.0-6ubuntu1~16.04.12+esm2

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

References:
https://ubuntu.com/security/notices/USN-5770-1
CVE-2017-11671