Improper Initialization in Linux kernel - CVE-2026-64310

Vulnerability identifier: #VU139664

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64310

CWE-ID: CWE-665

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper initialization in the SEV ioctl handling in drivers/crypto/ccp/sev-dev.c when processing /dev/sev ioctl commands that require only SEV firmware. A local user can issue a crafted SEV ioctl request to cause a host crash.

The issue can occur if SEV initialization fails while KVM is actively running normal virtual machines, leading to global clearing of MSR_VM_HSAVE_PA and a general protection fault on the next VMRUN.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1011.11, 7.0.0-1014.14
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1

• https://git.kernel.org/stable/c/5181e88da99c3d1d41e25db3472a62b8d4b42cdd
• https://git.kernel.org/stable/c/9e983d0a74a6a2348e4ce61647ec8a4dfbe198ac
• https://git.kernel.org/stable/c/d51207735e7c224cf591fa260c557a451a69a5cf
• https://git.kernel.org/stable/c/fb1758e74b8061aacfbce7bbb7a7cc650537e167

• Improper Initialization in Linux kernel crypto ccp driver
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-azure
• Ubuntu update for linux-azure-7.0