CVE-2026-89932

Summary

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

KVM: nVMX: Always flush vpid02 on first use

Make sure vpid02 is always flushed on first use by setting last_vpid=0 when allocating vpid02. nested_vmx_transition_tlb_flush() will always detect a VPID change on first VM-Enter after VMXON, because VPID=0 in vmcs12 is not allowed if L1 enables VPID.

This avoids using stale TLB entries from a previous lifetime of the VPID, that might have been associated with a different vCPU (or a completely different VM).

Note that last_vpid is already being initialized as 0 when the vCPU is created, but it is not reset when vpid02 is freed on VMXOFF. Hence, the problem can only occur if L1 does VMXOFF -> VMXON, runs an L2, and KVM happens to reuse a VPID that has TLB entries on the physical CPU.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/26de0d2d9a8d14c03e5ebb25fd68b5bfcd5ac366
• https://git.kernel.org/stable/c/8bc609999ec223089fec8d74c7de27d689606b36
• https://git.kernel.org/stable/c/62604376c313178811375f40a282fc2a46cd2311
• https://git.kernel.org/stable/c/8b98d662ab24f34710a56e03bc9169e4a5508606
• https://git.kernel.org/stable/c/22dfcc22c95e91295119a1c3b469816ce44c4804
• https://git.kernel.org/stable/c/121991d150735f3c0f7401678ce4d35c5b4ac898
• https://git.kernel.org/stable/c/f0772389413dce9657c7d6950abf3edbbd511356

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