CVE-2026-64561Public exploit

Guest-to-host code execution via shadow-page use-after-free

Published Aug 4, 2026 · Updated Aug 4, 2026

Use-after-free in KVM/x86 in affected Linux kernels allows guest OS users to execute code as root on the host through nested virtualization. The recursive shadow-MMU zap path reclaims an in-use root, then fault handling maps through that invalid root and creates invalid child pages on the active list, enabling host-kernel list corruption. Exploitation requires root in a nested-capable guest; AMD hosts have no additional constraint, while Intel hosts must expose both four- and five-level EPT walks, and successful exploitation compromises the host and co-located guests.

CVSS severity8.8
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in KVM/x86 in affected Linux kernels allows guest OS users to execute code as root on the host through nested virtualization. The recursive shadow-MMU zap path reclaims an in-use root, then fault handling maps through that invalid root and creates invalid child pages on the active list, enabling host-kernel list corruption. Exploitation requires root in a nested-capable guest; AMD hosts have no additional constraint, while Intel hosts must expose both four- and five-level EPT walks, and successful exploitation compromises the host and co-located guests.

The record

CVE
CVE-2026-64561
Published
Aug 4, 2026
Updated
Aug 4, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-825, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.9
  2. Affected versionversion=f95eec9bed76d42194c23153cb1cc8f186bf91cb <0026dbb7de8ea76e97d6edf42fc3cc084564e2bf
  3. Affected versionversion=f95eec9bed76d42194c23153cb1cc8f186bf91cb <2abd5287f08319fa35764566b15c6e22cb1068db
  4. Affected versionversion=f95eec9bed76d42194c23153cb1cc8f186bf91cb <35e77467610c4a37cb0ff54ee56b85f73b1f5700
  5. Affected versionversion=f95eec9bed76d42194c23153cb1cc8f186bf91cb <bce0d3c26e2c761a4bf43c8949f333fc7374eb2d
  6. Affected versionversion=f95eec9bed76d42194c23153cb1cc8f186bf91cb <f3477a6a4164f15287444eda685b5f6405dbd1e5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.9; version=f95eec9bed76d42194c23153cb1cc8f186bf91cb <0026dbb7de8ea76e97d6edf42fc3cc084564e2bf; version=f95eec9bed76d42194c23153cb1cc8f186bf91cb <2abd5287f08319fa35764566b15c6e22cb1068db; version=f95eec9bed76d42194c23153cb1cc8f186bf91cb <35e77467610c4a37cb0ff54ee56b85f73b1f5700; version=f95eec9bed76d42194c23153cb1cc8f186bf91cb <bce0d3c26e2c761a4bf43c8949f333fc7374eb2d; version=f95eec9bed76d42194c23153cb1cc8f186bf91cb <f3477a6a4164f15287444eda685b5f6405dbd1e5

Published CVSS scores

8.8Linux CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
7.0OracleCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-825Expired Pointer Dereference
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

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