SB20261022324 - Race condition in Linux kernel kvm svm

Description

This security bulletin contains information about 1 vulnerability.

1) Race condition (CVE-ID: CVE-2026-98718)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 5.8 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to corrupt data in host memory reallocated to another owner.

The vulnerability exists due to a race condition in the Linux kernel KVM SEV sev_migrate_from() function when intra-host migration overlaps with memory reclamation. A local user can exploit the interval between clearing the source VM's SEV active state and flushing its caches to cause stale guest ciphertext to overwrite data in a freed and reallocated page.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/8b7d4f68fef96cebe0b6dbb6e5607772337f7369
• https://git.kernel.org/stable/c/973ea70393e885e540f714904e51bc6cac80e3d7
• https://git.kernel.org/stable/c/de83ff6a4d8f3618473bedb3c4400020c22e8a8a