CVE-2026-72277: KVM: arm64: nv: Inject SEA if guest VNCR isn't normal memory

CVE-2026-72277: KVM: arm64: nv: Inject SEA if guest VNCR isn't normal memory

[Greg Kroah-Hartman]

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

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

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

KVM: arm64: nv: Inject SEA if guest VNCR isn't normal memory

When constructing an L1 VNCR mapping, KVM unconditionally uses cacheable
memory attributes, even if the underlying PFN isn't memory. This gets
particularly hairy if the endpoint doesn't support cacheable memory
attributes, potentially throwing an SError on writeback...

While KVM does permit cacheable memory attributes on certain PFNMAP
VMAs, kvm_translate_vncr() isn't currently grabbing the VMA. So do the
simpler thing for now and just reject everything that isn't memory.

The Linux kernel CVE team has assigned CVE-2026-72277 to this issue.


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

	Issue introduced in 6.16 with commit 2a359e072596fcb2e9e85017a865e3618a2fe5b5 and fixed in 6.18.40 with commit d5436e18e4fc2886ac306304d884ea3b92e1edbf
	Issue introduced in 6.16 with commit 2a359e072596fcb2e9e85017a865e3618a2fe5b5 and fixed in 7.1.5 with commit bc00e0e376ee3572f5d26c174473abef1e35decc
	Issue introduced in 6.16 with commit 2a359e072596fcb2e9e85017a865e3618a2fe5b5 and fixed in 7.2-rc4 with commit 4bd7dbe0b2243e6aa735cae4d5e1ff988b30b2a6

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-2026-72277
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/arm64/kvm/nested.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/d5436e18e4fc2886ac306304d884ea3b92e1edbf
	https://git.kernel.org/stable/c/bc00e0e376ee3572f5d26c174473abef1e35decc
	https://git.kernel.org/stable/c/4bd7dbe0b2243e6aa735cae4d5e1ff988b30b2a6