Vulnerability in Linux

[ Description ]Official description

In the Linux kernel, the following vulnerability has been resolved: KVM: nVMX: Force MSR bitmap refresh if runtime eVMCS controls are modified Force a refresh of the vmcs02 MSR bitmap during nested VM-Enter if the runtime eVMCS controls (pin, primary, secondary, etc.) are being updated. If L1 isn't intercepting TPR writes, runs L2 with TPR virtualization, and then runs the same L2 with TPR virtualization disabled, KVM will fail to refresh msr_bitmap02 and leave TPR in passthrough mode even though TPR virtualization is disabled. I.e. failure to refresh the bitmap lets L2 (or L1 by proxy) read and write L0's TPR.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund18 Oct 2026WID-SEC-2026-4019

  Linux Kernel: Multiple vulnerabilities Translated from German

  CVE-2026-98866CVE-2026-98624CVE-2026-98745+326 more CVEs

[ References ]References

• git.kernel.org/stable/c/1e497e3bdab6983deb68a1d26b488027deb4527f
• git.kernel.org/stable/c/2abb25273c82061dd4670690c81c319c03740bf6
• git.kernel.org/stable/c/2db11598b59f16ddb6420693f9a4ac4efc3d4789
• git.kernel.org/stable/c/f6189e26d0237e47e2f04f9cb1e43fd19a9b2f3a