CVE-2026-43483 is a vulnerability in Linux Kernel
Published on May 13, 2026
KVM: SVM: Set/clear CR8 write interception when AVIC is (de)activated
In the Linux kernel, the following vulnerability has been resolved:
KVM: SVM: Set/clear CR8 write interception when AVIC is (de)activated
Explicitly set/clear CR8 write interception when AVIC is (de)activated to
fix a bug where KVM leaves the interception enabled after AVIC is
activated. E.g. if KVM emulates INIT=>WFS while AVIC is deactivated, CR8
will remain intercepted in perpetuity.
On its own, the dangling CR8 intercept is "just" a performance issue, but
combined with the TPR sync bug fixed by commit d02e48830e3f ("KVM: SVM:
Sync TPR from LAPIC into VMCB::V_TPR even if AVIC is active"), the danging
intercept is fatal to Windows guests as the TPR seen by hardware gets
wildly out of sync with reality.
Note, VMX isn't affected by the bug as TPR_THRESHOLD is explicitly ignored
when Virtual Interrupt Delivery is enabled, i.e. when APICv is active in
KVM's world. I.e. there's no need to trigger update_cr8_intercept(), this
is firmly an SVM implementation flaw/detail.
WARN if KVM gets a CR8 write #VMEXIT while AVIC is active, as KVM should
never enter the guest with AVIC enabled and CR8 writes intercepted.
[Squash fix to avic_deactivate_vmcb. - Paolo]
Products Associated with CVE-2026-43483
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Affected Versions
Linux:- Version 3bbf3565f48ce3999b5a12cde946f81bd4475312 and below a4123fe5d9122eef9852e4921f7cc463420f30d4 is affected.
- Version 3bbf3565f48ce3999b5a12cde946f81bd4475312 and below 816fa1dfae4532e851b1fe6b2434c753ecbd86c7 is affected.
- Version 3bbf3565f48ce3999b5a12cde946f81bd4475312 and below 01651e7751edbbc0fb4598f8367a3dabcfc8c182 is affected.
- Version 3bbf3565f48ce3999b5a12cde946f81bd4475312 and below ba3bca40f9f25c053f69413e5f4a41dd0fd762bf is affected.
- Version 3bbf3565f48ce3999b5a12cde946f81bd4475312 and below 737410b32bd615b321da4fbeda490351b9af5e8b is affected.
- Version 3bbf3565f48ce3999b5a12cde946f81bd4475312 and below 87d0f901a9bd8ae6be57249c737f20ac0cace93d is affected.
- Version 4.7 is affected.
- Before 4.7 is unaffected.
- Version 6.1.167, <= 6.1.* is unaffected.
- Version 6.6.130, <= 6.6.* is unaffected.
- Version 6.12.78, <= 6.12.* is unaffected.
- Version 6.18.19, <= 6.18.* is unaffected.
- Version 6.19.9, <= 6.19.* is unaffected.
- Version 7.0, <= * is unaffected.