CVE-2026-64310
Received Received - Intake

Memory Corruption in Linux Kernel Crypto CCP

Publication date: 2026-07-25

Last updated on: 2026-07-25

Assigner: kernel.org

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.

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Meta Information

Published
2026-07-25
Last Modified
2026-07-25
Generated
2026-07-25
AI Q&A
2026-07-25
EPSS Evaluated
N/A
NVD
CVE-2026-64310
EUVD
EUVD-2026-49022

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves improper handling of SEV (Secure Encrypted Virtualization) ioctls. When SEV initialization fails, a userspace process could trigger ioctls like SEV_PDH_GEN via /dev/sev, potentially zeroing out MSR_VM_HSAVE_PA globally. This might cause a general protection fault and crash the host during the next VMRUN execution for an active VM.

Detection Guidance

This vulnerability is specific to the Linux kernel's crypto subsystem and SEV (Secure Encrypted Virtualization) functionality. Detection requires checking kernel logs for SEV-related errors or examining the kernel version for the presence of the vulnerable code path. Commands like 'dmesg | grep -i sev' or 'journalctl -k | grep -i sev' may help identify SEV-related issues. Ensure your kernel is updated to a patched version.

Impact Analysis

If exploited, this vulnerability could lead to system crashes or instability by corrupting critical virtualization state. Attackers with local access might trigger the issue to cause denial-of-service conditions on affected systems running KVM with SEV-enabled VMs.

Mitigation Strategies

Apply the latest kernel update that includes the fix for this vulnerability. Reboot the system to ensure the updated kernel is active. Monitor SEV-related operations and logs for any unusual activity. If SEV is not actively used, consider disabling it via kernel parameters until fully patched.

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