Linux kernel KVM SVM: INVLPGA does not raise #UD with EFER.SVME clear

CVSS 5.5CVE-2026-46082Kernel, userspace & hypervisorcurated

Impact

On AMD hosts, KVM did not inject #UD for a guest INVLPGA executed with EFER.SVME clear, where the architecture requires one. A guest therefore sees behaviour that deviates from real hardware: an instruction that should fault instead executes. The record describes no host memory-safety consequence, no cross-tenant effect and no escape - the impact is architectural correctness, which matters mainly to guests that probe or depend on SVM instruction faulting. Treat this as a low-urgency correctness fix to pick up with the next kernel update rather than a reason to open a window.

Who can reach it

Local, from inside a guest on an AMD host: guest kernel-level code (CPL0) executing INVLPGA with EFER.SVME clear. No host access needed, but no host-side gain is described either.

What to do

Pick up the fix with the next host kernel update on AMD hypervisor nodes and reboot as part of normal maintenance; nothing in the record justifies an out-of-band window. No mitigation is given.

References

https://nvd.nist.gov/vuln/detail/CVE-2026-46082 https://git.kernel.org/stable/c/3ac9d4241d205f5d0df06358349ca718ebb0fa12 https://git.kernel.org/stable/c/643125b66ffc1147c66616b749475ba9efb15971 https://git.kernel.org/stable/c/d99df02ff427f461102230f9c5b90a6c64ee8e23

This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.