CVE-2026-98164

KVM: x86/mmu: Check write tracking in all address spaces

State: Published
Severity: 7.1 High
Published: Sep 29, 2026
Updated: Oct 7, 2026
Reserved: Sep 25, 2026

Description

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

KVM: x86/mmu: Check write tracking in all address spaces

kvm_gfn_is_write_tracked() checks only the supplied memslot, but page tracking is per-address-space and shadow pages are shared across all address spaces. With SMM, a GFN can therefore be write-tracked in one address space and appear untracked through the other.

Check the supplied slot first, then the slot for the other address space. This ensures all callers honor write tracking regardless of the active address space. In particular, it prevents mmu_try_to_unsync_pages() from marking an upper-level shadow page unsync and eventually triggering the BUG in pte_list_remove().

[invert direction of the conditional. - Paolo]

Scores

CVSS	Score	Vector	Source
3.1	7.1 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	699023e239658e62da6f42f47d31b54788521ec1 to before 09aa68552d2542cc6c23edd1568ac265dc5d886fAffected 699023e239658e62da6f42f47d31b54788521ec1 to before 429b6f43b4d8c98988fdca99e02dc156134e3d77Affected 699023e239658e62da6f42f47d31b54788521ec1 to before d8636c8f9f95d0fd1e2f6f1cad0d5757aa6f212aAffected 699023e239658e62da6f42f47d31b54788521ec1 to before c0a9bd5fca0b5f2dea32b0fc31350e71e8648112Affected 699023e239658e62da6f42f47d31b54788521ec1 to before ec8fcaf354c1cbb36755d48e9f5a00c9591349e5Affected 699023e239658e62da6f42f47d31b54788521ec1 to before 0f38453cdb2e17566ccb7c0f3dabd5bd21caca26Affected
LinuxLinux	4.2Affected before 4.2Not affected 6.1.187 through 6.1.Not affected 6.6.156 through 6.6.Not affected 6.12.108 through 6.12.Not affected 6.18.49 through 6.18.Not affected 7.1.13 through 7.1.*Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

699023e239658e62da6f42f47d31b54788521ec1 to before 09aa68552d2542cc6c23edd1568ac265dc5d886fAffected
699023e239658e62da6f42f47d31b54788521ec1 to before 429b6f43b4d8c98988fdca99e02dc156134e3d77Affected
699023e239658e62da6f42f47d31b54788521ec1 to before d8636c8f9f95d0fd1e2f6f1cad0d5757aa6f212aAffected
699023e239658e62da6f42f47d31b54788521ec1 to before c0a9bd5fca0b5f2dea32b0fc31350e71e8648112Affected
699023e239658e62da6f42f47d31b54788521ec1 to before ec8fcaf354c1cbb36755d48e9f5a00c9591349e5Affected
699023e239658e62da6f42f47d31b54788521ec1 to before 0f38453cdb2e17566ccb7c0f3dabd5bd21caca26Affected

LinuxLinux

4.2Affected
before 4.2Not affected
6.1.187 through 6.1.*Not affected
6.6.156 through 6.6.*Not affected
6.12.108 through 6.12.*Not affected
6.18.49 through 6.18.*Not affected
7.1.13 through 7.1.*Not affected
7.2 and laterNot affected

References

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