A linux security update has been released for Debian GNU/Linux 12 to address an issue that may result in the leakage of sensitive information across concurrent processes, hyper threads and virtualized guests on AMD Zen2 CPUs.

[SECURITY] [DSA 5462-1] linux security update

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Debian Security Advisory DSA-5462-1 security@debian.org
https://www.debian.org/security/ Salvatore Bonaccorso
July 30, 2023 https://www.debian.org/security/faq
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Package : linux
CVE ID : CVE-2023-20593

Tavis Ormandy discovered that under specific microarchitectural
circumstances, a vector register in AMD "Zen 2" CPUs may not be
written to 0 correctly. This flaw allows an attacker to leak
sensitive information across concurrent processes, hyper threads
and virtualized guests.

For details please refer to
( https://lock.cmpxchg8b.com/zenbleed.html) and
( https://github.com/google/security-research/security/advisories/GHSA-v6wh-rxpg-cmm8) .

This issue can also be mitigated by a microcode update through the
amd64-microcode package or a system firmware (BIOS/UEFI) update.
However, the initial microcode release by AMD only provides
updates for second generation EPYC CPUs. Various Ryzen CPUs are
also affected, but no updates are available yet.

For the stable distribution (bookworm), this problem has been fixed in
version 6.1.38-2.

We recommend that you upgrade your linux packages.

For the detailed security status of linux please refer to its security
tracker page at:
https://security-tracker.debian.org/tracker/linux

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/