CVE-2026-72286: KVM: SEV: Do not allow intra-host migration/mirroring of SNP VMs

CVE-2026-72286: KVM: SEV: Do not allow intra-host migration/mirroring of SNP VMs

[Greg Kroah-Hartman]

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

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

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

KVM: SEV: Do not allow intra-host migration/mirroring of SNP VMs

The intra-host migration/mirroring feature is not fully implemented for
SEV-SNP VMs. The proper migration requires additional SNP-specific
state such as guest_req_mutex, guest_req_buf, and guest_resp_buf to be
transferred or initialized on the destination.

The SNP VM mirroring requires vmsa features to be copied as well otherwise
ASID would be bound to SNP range while VM is detected as a SEV VM.

Reject SNP source VMs in migration/mirroring until proper SNP state
transfer is implemented.


[sean: let lines poke past 80 chars, tag for stable]

The Linux kernel CVE team has assigned CVE-2026-72286 to this issue.


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

	Issue introduced in 6.11 with commit 1dfe571c12cf99244b933208fb77f29471ded677 and fixed in 6.12.97 with commit b70404b89daad5f9f33f7ac640b1065cba639935
	Issue introduced in 6.11 with commit 1dfe571c12cf99244b933208fb77f29471ded677 and fixed in 6.18.40 with commit ba06690b28be950bd46d938d9b919c4024292627
	Issue introduced in 6.11 with commit 1dfe571c12cf99244b933208fb77f29471ded677 and fixed in 7.1.5 with commit d2f9df3b615ca0cd45899c090366945528186052
	Issue introduced in 6.11 with commit 1dfe571c12cf99244b933208fb77f29471ded677 and fixed in 7.2-rc4 with commit 6ee4140788234a6fabf59e6a50e38cdb936008cd

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-2026-72286
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/kvm/svm/sev.c


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/b70404b89daad5f9f33f7ac640b1065cba639935
	https://git.kernel.org/stable/c/ba06690b28be950bd46d938d9b919c4024292627
	https://git.kernel.org/stable/c/d2f9df3b615ca0cd45899c090366945528186052
	https://git.kernel.org/stable/c/6ee4140788234a6fabf59e6a50e38cdb936008cd