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CVE-2026-98164

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

Linux LinuxOperating systems
Open in ThreatlineRecord JSON
CVSS
7.1High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.15%Chance of exploitation activity in the next 30 days, higher than 3% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in09aa68552d2542cc6c23edd1568ac265dc5d886fAlso 429b6f43b4d8c98988fdca99e02dc156134e3d77, 0f38453cdb2e17566ccb7c0f3dabd5bd21caca26CVE List
Published29 Sep 2026Updated 7 Oct 2026CVE List

What fixes it

  • 09aa68552d2542cc6c23edd1568ac265dc5d886fLinuxCVE List
  • 429b6f43b4d8c98988fdca99e02dc156134e3d77LinuxCVE List
  • 0f38453cdb2e17566ccb7c0f3dabd5bd21caca26LinuxCVE List

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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]

Text from CVE List

Affected versions 14

  • Linuxaffected: 699023e239658e62da6f42f47d31b54788521ec1 before 09aa68552d2542cc6c23edd1568ac265dc5d886fCVE List
  • Linuxaffected: 699023e239658e62da6f42f47d31b54788521ec1 before 429b6f43b4d8c98988fdca99e02dc156134e3d77CVE List
  • Linuxaffected: 699023e239658e62da6f42f47d31b54788521ec1 before d8636c8f9f95d0fd1e2f6f1cad0d5757aa6f212aCVE List
  • Linuxaffected: 699023e239658e62da6f42f47d31b54788521ec1 before c0a9bd5fca0b5f2dea32b0fc31350e71e8648112CVE List
  • Linuxaffected: 699023e239658e62da6f42f47d31b54788521ec1 before ec8fcaf354c1cbb36755d48e9f5a00c9591349e5CVE List
  • Linuxaffected: 699023e239658e62da6f42f47d31b54788521ec1 before 0f38453cdb2e17566ccb7c0f3dabd5bd21caca26CVE List
  • Linuxaffected: 4.2CVE List
  • Linuxunaffected: all versions before 4.2CVE List
  • Linuxunaffected: 6.1.187 through 6.1.*CVE List
  • Linuxunaffected: 6.6.156 through 6.6.*CVE List
  • Linuxunaffected: 6.12.108 through 6.12.*CVE List
  • Linuxunaffected: 6.18.49 through 6.18.*CVE List
  • Linuxunaffected: 7.1.13 through 7.1.*CVE List
  • Linuxunaffected: 7.2CVE List

References 6