--- id: CVE-2026-64561 title: |- 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 summary: |- 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… severity: high cvss: 8.8 cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H' published: '2026-08-04' updated: '2026-08-08' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64561' references: - url: 'https://git.kernel.org/stable/c/0026dbb7de8ea76e97d6edf42fc3cc084564e2bf' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/2abd5287f08319fa35764566b15c6e22cb1068db' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/35e77467610c4a37cb0ff54ee56b85f73b1f5700' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/bce0d3c26e2c761a4bf43c8949f333fc7374eb2d' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/f3477a6a4164f15287444eda685b5f6405dbd1e5' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/62ef67af1878fa2cd066642f2f59e33ade95f637' - url: 'https://git.kernel.org/stable/c/65c4f7a1028cf01a93a2762d679c289810ede990' - url: 'https://github.com/V4bel/Zapscape' - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64561.json - url: 'https://access.redhat.com/security/cve/CVE-2026-64561' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2510891' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-64561' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64561' - url: >- https://lore.kernel.org/linux-cve-announce/2026080401-CVE-2026-64561-d0d4@gregkh/T - url: 'https://access.redhat.com/errata/RHSA-2026:49030' - url: 'https://access.redhat.com/errata/RHSA-2026:45114' - url: 'https://access.redhat.com/errata/RHSA-2026:48386' - url: 'https://access.redhat.com/errata/RHSA-2026:49031' - url: 'https://access.redhat.com/errata/RHSA-2026:45192' - url: 'https://access.redhat.com/errata/RHSA-2026:45115' - url: 'https://access.redhat.com/errata/RHSA-2026:47869' - url: 'https://access.redhat.com/errata/RHSA-2026:45116' tags: - nvd - exploit-available - cve.org - csaf - vex - red-hat epss: 0.00273 epssPercentile: 0.19512 ingestedAt: '2026-08-08T19:28:33.532Z' exploits: github: 8 githubRepos: - 'https://github.com/HORKimhab/CVE-2026-64561' - 'https://github.com/HackSpeak/CVE-2026-64561' - 'https://github.com/Aoripus-LTD/Zapscape-Fix' checkedAt: '2026-10-27T19:07:30.972Z' exploitAvailable: true vendor: Linux product: Linux affected: - >- Linux >= f95eec9bed76d42194c23153cb1cc8f186bf91cb < 62ef67af1878fa2cd066642f2f59e33ade95f637 - >- Linux >= f95eec9bed76d42194c23153cb1cc8f186bf91cb < 65c4f7a1028cf01a93a2762d679c289810ede990 - >- Linux >= f95eec9bed76d42194c23153cb1cc8f186bf91cb < 35e77467610c4a37cb0ff54ee56b85f73b1f5700 - >- Linux >= f95eec9bed76d42194c23153cb1cc8f186bf91cb < 0026dbb7de8ea76e97d6edf42fc3cc084564e2bf - >- Linux >= f95eec9bed76d42194c23153cb1cc8f186bf91cb < f3477a6a4164f15287444eda685b5f6405dbd1e5 - >- Linux >= f95eec9bed76d42194c23153cb1cc8f186bf91cb < bce0d3c26e2c761a4bf43c8949f333fc7374eb2d - >- Linux >= f95eec9bed76d42194c23153cb1cc8f186bf91cb < 2abd5287f08319fa35764566b15c6e22cb1068db - Linux 5.9 ssvc: exploitation: none automatable: 'no' technicalImpact: total timestamp: '2026-10-16T15:42:48.794184Z' patched: - enterprise_linux_appstream_eus_v_10_0 - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_e4s_v_9_4 - enterprise_linux_appstream_eus_v_9_6 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_eus_v_10_0 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_e4s_v_8_8 - enterprise_linux_baseos_tus_v_8_8 - enterprise_linux_baseos_e4s_v_9_4 - enterprise_linux_baseos_eus_v_9_6 - enterprise_linux_baseos_v_9 - enterprise_linux_codeready_linux_builder_eus_v_10_0 - enterprise_linux_codeready_linux_builder_v_10 - enterprise_linux_crb_v_8 - codeready_linux_builder_eus_v_9_6 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_real_time_for_nfv_eus_v_10_0 - enterprise_linux_real_time_for_nfv_v_10 - enterprise_linux_nfv_v_8 - enterprise_linux_real_time_for_nfv_e4s_v_9_4 - enterprise_linux_real_time_for_nfv_eus_v_9_6 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_real_time_eus_v_10_0 - enterprise_linux_real_time_v_10 - enterprise_linux_rt_v_8 - enterprise_linux_real_time_e4s_v_9_4 - enterprise_linux_real_time_eus_v_9_6 - enterprise_linux_real_time_v_9 cwe: - CWE-825 scores: nvd: 8.8 vendor: 7 cna: 8.8 --- ## Overview 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. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **RHSA-2026:49030** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0), Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0), Red Hat Enterprise Linux Real Time EUS (v. 10.0) · released 2026-07-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:49030) - **RHSA-2026:45114** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), Red Hat Enterprise Linux Real Time (v. 10) · released 2026-07-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:45114) - **RHSA-2026:48386** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4), Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4), Red Hat Enterprise Linux Real Time E4S (v.9.4) · released 2026-07-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:48386) - **RHSA-2026:49031** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.6), Red Hat Enterprise Linux BaseOS EUS (v.9.6), Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6), Red Hat Enterprise Linux Real Time EUS (v.9.6) · released 2026-07-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:49031) - **RHSA-2026:45192** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-07-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:45192) - **RHSA-2026:45115** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-07-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:45115) - **RHSA-2026:47869** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS E4S (v.8.8), Red Hat Enterprise Linux BaseOS TUS (v.8.8) · released 2026-07-29 · [advisory](https://access.redhat.com/errata/RHSA-2026:47869) - **RHSA-2026:45116** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-07-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:45116) - **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 9 · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64561.json)