CVE-2026-64310 crypto: ccp - Do not initialize SNP for SEV ioctls

What is CVE-2026-64310?

CVE-2026-64310 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official 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 and hardcoded the return value of INVALID_PLATFORM_STATE regardless of the real firmware error. This patch changes it to surface the underlying error, which is hopefully both more useful and doesn't cause any problems.

Note that it is still safe to call __sev_firmware_shutdown() directly: it calls __sev_snp_shutdown_locked(), which skips SNP shutdown if SNP was not initialized.

Which versions are affected by CVE-2026-64310?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-64310?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-64310 being exploited?

There is no known exploitation of CVE-2026-64310 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-64310, DEBIAN-CVE-2026-64310, GHSA-cfm2-f7px-wg9f, ROOT-OS-UBUNTU-2204-CVE-2026-64310, UBUNTU-CVE-2026-64310.