CVE-2026-64310

Technical Description

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

crypto: ccp - Do not initialize SNP for SEV ioctls

Sashiko notes:

> if SEV initialization fails and KVM is actively running normal VMs, could a

> userspace process trigger this code path via /dev/sev ioctls (e.g.,

> SEV_PDH_GEN) and zero out MSR_VM_HSAVE_PA globally? Would the next VMRUN

> execution for an active VM trigger a general protection fault and crash the

> host?

sev_move_to_init_state() is called for ioctls requiring only SEV firmware:

SEV_PEK_GEN, SEV_PDH_GEN, SEV_PEK_CSR, SEV_PEK_CERT_IMPORT, and

SEV_PDH_CERT_EXPORT. After the firmware command, it does SEV_SHUTDOWN on

the SEV firmware. Since these commands do not require SNP to be

initialized, skip it by calling __sev_platform_init_locked() which only

initializes the SEV firmware. This way SNP is not Initialized at all, and

HSAVE_PA is not cleared.

The previous code saved any SEV initialization firmware error to

init_args.error and then threw it away a

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. 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.

References