CVE-2026-72283: KVM: x86: Nullify irqfd->producer if updating IRTE for bypass fails

CVE-2026-72283: KVM: x86: Nullify irqfd->producer if updating IRTE for bypass fails

[Greg Kroah-Hartman]

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

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

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

KVM: x86: Nullify irqfd->producer if updating IRTE for bypass fails

Nullify irqfd->producer if updating the IRTE for bypass fails, as leaving a
dangling pointer will result in a use-after-free if the irqfd is reachable
through KVM's routing, but the producer is freed separately.  E.g. for VFIO
PCI, the producer is embedded in struct "vfio_pci_irq_ctx" and freed when
the vector is disabled, which can happen independent of routing updates.

[sean: drop PPC change, massage changelog]

The Linux kernel CVE team has assigned CVE-2026-72283 to this issue.


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

	Issue introduced in 6.17 with commit 77e1b8332d1d7aa786f7515e9bd4055def6a1e06 and fixed in 6.18.40 with commit d1379888cc4230bac647ec24ab83306afbd03e88
	Issue introduced in 6.17 with commit 77e1b8332d1d7aa786f7515e9bd4055def6a1e06 and fixed in 7.1.5 with commit d5560b6569cd05ba72c6b33427fbabc6ec46b8cf
	Issue introduced in 6.17 with commit 77e1b8332d1d7aa786f7515e9bd4055def6a1e06 and fixed in 7.2-rc4 with commit ed446e8aa894883c08892cfee69782fdf8f6c3ca

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-2026-72283
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/irq.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/d1379888cc4230bac647ec24ab83306afbd03e88
	https://git.kernel.org/stable/c/d5560b6569cd05ba72c6b33427fbabc6ec46b8cf
	https://git.kernel.org/stable/c/ed446e8aa894883c08892cfee69782fdf8f6c3ca