You are viewing this page in an unauthorized frame window.
This is a potential security issue, you are being redirected to
https://nvd.nist.gov
An official website of the United States government
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.
In the Linux kernel, the following vulnerability has been resolved:
KVM: Explicitly verify target vCPU is online in kvm_get_vcpu()
Explicitly verify the target vCPU is fully online _prior_ to clamping the
index in kvm_get_vcpu(). If the index is "bad", the nospec clamping will
generate '0', i.e. KVM will return vCPU0 instead of NULL.
In practice, the bug is unlikely to cause problems, as it will only come
into play if userspace or the guest is buggy or misbehaving, e.g. KVM may
send interrupts to vCPU0 instead of dropping them on the floor.
However, returning vCPU0 when it shouldn't exist per online_vcpus is
problematic now that KVM uses an xarray for the vCPUs array, as KVM needs
to insert into the xarray before publishing the vCPU to userspace (see
commit c5b077549136 ("KVM: Convert the kvm->vcpus array to a xarray")),
i.e. before vCPU creation is guaranteed to succeed.
As a result, incorrectly providing access to vCPU0 will trigger a
use-after-free if vCPU0 is dereferenced and kvm_vm_ioctl_create_vcpu()
bails out of vCPU creation due to an error and frees vCPU0. Commit
afb2acb2e3a3 ("KVM: Fix vcpu_array[0] races") papered over that issue, but
in doing so introduced an unsolvable teardown conundrum. Preventing
accesses to vCPU0 before it's fully online will allow reverting commit
afb2acb2e3a3, without re-introducing the vcpu_array[0] UAF race.
Metrics
NVD enrichment efforts reference publicly available information to associate
vector strings. CVSS information contributed by other sources is also
displayed.
By selecting these links, you will be leaving NIST webspace.
We have provided these links to other web sites because they
may have information that would be of interest to you. No
inferences should be drawn on account of other sites being
referenced, or not, from this page. There may be other web
sites that are more appropriate for your purpose. NIST does
not necessarily endorse the views expressed, or concur with
the facts presented on these sites. Further, NIST does not
endorse any commercial products that may be mentioned on
these sites. Please address comments about this page to [email protected].
OR
*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.13.3
*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.78
*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.14
*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.179
*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.129
*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.5 up to (excluding) 5.10.235
*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.14.120 up to (excluding) 4.15
*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.19.44 up to (excluding) 4.20
*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.0.17 up to (excluding) 5.4.291
New CVE Received from kernel.org3/06/2025 12:15:21 PM
Action
Type
Old Value
New Value
Added
Description
In the Linux kernel, the following vulnerability has been resolved:
KVM: Explicitly verify target vCPU is online in kvm_get_vcpu()
Explicitly verify the target vCPU is fully online _prior_ to clamping the
index in kvm_get_vcpu(). If the index is "bad", the nospec clamping will
generate '0', i.e. KVM will return vCPU0 instead of NULL.
In practice, the bug is unlikely to cause problems, as it will only come
into play if userspace or the guest is buggy or misbehaving, e.g. KVM may
send interrupts to vCPU0 instead of dropping them on the floor.
However, returning vCPU0 when it shouldn't exist per online_vcpus is
problematic now that KVM uses an xarray for the vCPUs array, as KVM needs
to insert into the xarray before publishing the vCPU to userspace (see
commit c5b077549136 ("KVM: Convert the kvm->vcpus array to a xarray")),
i.e. before vCPU creation is guaranteed to succeed.
As a result, incorrectly providing access to vCPU0 will trigger a
use-after-free if vCPU0 is dereferenced and kvm_vm_ioctl_create_vcpu()
bails out of vCPU creation due to an error and frees vCPU0. Commit
afb2acb2e3a3 ("KVM: Fix vcpu_array[0] races") papered over that issue, but
in doing so introduced an unsolvable teardown conundrum. Preventing
accesses to vCPU0 before it's fully online will allow reverting commit
afb2acb2e3a3, without re-introducing the vcpu_array[0] UAF race.