CVE-2026-64561

High

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Check for invalid/obsolete root *after* making MMU pages available Check for a "stale" page fault, i.e. for an invalid and/or obsolete root, after making MMU pages available for the shadow MMU. If reclaiming shadow pages zaps an in-use root, i.e. marks it invalid, then KVM will attempt to map memory into an invalid root. On its own, populating an invalid root is "fine", but because child shadow pages inherit their parent's role, any children created during the map/fetch will be created as invalid pages, thus violating KVM's invariant that invalid pages are never on the list of active MMU pages. Note, the underlying flaw has existed since KVM first started tracking invalid roots in 2008 (commit 2e53d63acba7, "KVM: MMU: ignore zapped root pagetables"), but the true badness only came along in 2020 (Linux 5.9) with the invariant that invalid shadow pages can't be on the list of active pages. Note #2, inheriting role.invalid when creating child shadow pages is also far from ideal; that flaw will be addressed separately.

Package Linux Kernel
Published 2026-08-04
Last modified 2026-08-27
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

8.8

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected versions

Linux kernel versions 5.9 and later are affected. Fixed in 5.15.218, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6, 7.2 and their respective stable series.

Affected from
≥ 5.9
Fixed in
✓ 5.15.218 5.15.x ✓ 6.1.183 6.1.x ✓ 6.6.148 6.6.x ✓ 6.12.101 6.12.x ✓ 6.18.42 6.18.x ✓ 7.1.6 7.1.x ✓ 7.2

References

8 total
Showing 5 of 8 references View all on NVD

Frequently asked questions

  • What is CVE-2026-64561?

    CVE-2026-64561 is a High severity Linux kernel vulnerability with a CVSS score of 8.8 out of 10 . It affects Linux kernel versions from 5.9 onward and has been patched in 5.15.218, 6.1.183, 6.6.148 and others. CVE-2026-64561 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-64561?

    CVE-2026-64561 has a CVSS score of 8.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H .

  • Is there a patch available for CVE-2026-64561?

    Yes. CVE-2026-64561 has been patched. Fixed versions include 5.15.218, 6.1.183, 6.6.148 and others. If you are running Linux kernel 5.9 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-64561 actively exploited?

    No. CVE-2026-64561 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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