CVE-2026-43315

Technical Description

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

KVM: nSVM: Remove a user-triggerable WARN on nested_svm_load_cr3() succeeding

Drop the WARN in svm_set_nested_state() on nested_svm_load_cr3() failing

as it is trivially easy to trigger from userspace by modifying CPUID after

loading CR3. E.g. modifying the state restoration selftest like so:

--- tools/testing/selftests/kvm/x86/state_test.c

+++ tools/testing/selftests/kvm/x86/state_test.c

@@ -280,7 +280,16 @@ int main(int argc, char *argv[])

/* Restore state in a new VM. */

vcpu = vm_recreate_with_one_vcpu(vm);

- vcpu_load_state(vcpu, state);

+

+ if (stage == 4) {

+ state->sregs.cr3 = BIT(44);

+ vcpu_load_state(vcpu, state);

+

+ vcpu_set_cpuid_property(vcpu, X86_PROPERTY_MAX_PHY_ADDR, 36);

+ __vcpu_nested_state_set(vcpu, &state->nested);

+

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References