CVE-2026-46174: x86/CPU/AMD: Prevent improper isolation of shared resources in Zen2's op cache

CVE-2026-46174: x86/CPU/AMD: Prevent improper isolation of shared resources in Zen2's op cache

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

x86/CPU/AMD: Prevent improper isolation of shared resources in Zen2's op cache

Make sure resources are not improperly shared in the op cache and
cause instruction corruption this way.

The Linux kernel CVE team has assigned CVE-2026-46174 to this issue.


Affected and fixed versions
===========================

	Fixed in 5.10.256 with commit 1e23b30a80b14e5764657401ee2cca030525ae8e
	Fixed in 5.15.207 with commit f5bc3aef7df46eaaf423d7413ab8833f704ae576
	Fixed in 6.1.173 with commit 251497955f2314cd39d43191e81c6151dead4c7b
	Fixed in 6.6.139 with commit ff6fc65b3bf73acc5ee71919154d830ad5431362
	Fixed in 6.12.88 with commit 9109489cc8c34e50d15575a3d1ff82af586bc1aa
	Fixed in 6.18.30 with commit 28f5ed477eef166d678d6966762cbc1de9b4f436
	Fixed in 7.0.7 with commit 1cd85a19748b2407830376a5cbae5c0f126016e5
	Fixed in 7.1-rc4 with commit c21b90f77687075115d989e53a8ec5e2bb427ab1

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-46174
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	arch/x86/include/asm/msr-index.h
	arch/x86/kernel/cpu/amd.c
	tools/arch/x86/include/asm/msr-index.h


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/1e23b30a80b14e5764657401ee2cca030525ae8e
	https://git.kernel.org/stable/c/f5bc3aef7df46eaaf423d7413ab8833f704ae576
	https://git.kernel.org/stable/c/251497955f2314cd39d43191e81c6151dead4c7b
	https://git.kernel.org/stable/c/ff6fc65b3bf73acc5ee71919154d830ad5431362
	https://git.kernel.org/stable/c/9109489cc8c34e50d15575a3d1ff82af586bc1aa
	https://git.kernel.org/stable/c/28f5ed477eef166d678d6966762cbc1de9b4f436
	https://git.kernel.org/stable/c/1cd85a19748b2407830376a5cbae5c0f126016e5
	https://git.kernel.org/stable/c/c21b90f77687075115d989e53a8ec5e2bb427ab1

Re: CVE-2026-46174: x86/CPU/AMD: Prevent improper isolation of shared resources in Zen2's op cache

[Brendan Jackman]

Hi Greg,

This is https://nvd.nist.gov/vuln/detail/cve-2025-54518 right? I suppose we
shouldn't have a separate CVE for the kernel patch.

On the other hand I dunno if this actually matters very much.

Cheers,
Brendan