Debian 9812 Published by

An amd64-microcode security update has been released for Debian GNU/Linux 11 and 12 to address a flaw in the vector register of Zen 2 CPUs.

[SECURITY] [DSA 5459-1] amd64-microcode security update

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Debian Security Advisory DSA-5459-1 Salvatore Bonaccorso
July 25, 2023
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Package : amd64-microcode
CVE ID : CVE-2023-20593
Debian Bug : 1041863

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

For details please refer to

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. Fixes will be provided in a later update once
they are released.

For more specific details and target dates please refer to the AMD
advisory at

For the oldstable distribution (bullseye), this problem has been fixed
in version 3.20230719.1~deb11u1. Additionally the update contains a fix
for CVE-2019-9836.

For the stable distribution (bookworm), this problem has been fixed in
version 3.20230719.1~deb12u1.
We recommend that you upgrade your amd64-microcode packages.

For the detailed security status of amd64-microcode please refer to
its security tracker page at:

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: