CVE-2026-64285 Details
Description
In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Pin source page for write when adding CPUID data for SNP guest When populating a guest_memfd instance with the initial CPUID data for an SNP guest, acquire a writable pin on the source page as KVM will write back the "correct" CPUID information if the userspace provided data is rejected by trusted firmware. Because KVM writes to the source page using a kernel mapping, pinning for read could result in KVM clobbering read-only memory. Note, well-behaved VMMs are unlikely to be affected, as CPUID information is almost always dynamically generated by userspace, i.e. it's unlikely for the CPUID information to be backed by a read-only mapping. [sean: rewrite shortlog and changelog, tag for stable@]
A vulnerability in the Linux kernel's KVM (Kernel-based Virtual Machine) module affects the handling of CPUID data for SNP (Secure Nested Paging) guests. When initializing a guest_memfd instance with CPUID data, the kernel must pin the source page for writing. This is necessary because KVM may need to overwrite the CPUID information if the data provided by userspace is rejected by trusted firmware. The vulnerability arises because KVM writes to the source page using a kernel mapping, which can lead to clobbering read-only memory. While this issue is unlikely to affect well-behaved Virtual Machine Monitors (VMMs) that dynamically generate CPUID information through userspace, it still represents a potential risk in certain scenarios.
Users can upgrade to the latest version of the Linux kernel where this vulnerability has been addressed. Instructions for upgrading the kernel can be found in the official Linux documentation.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/dcdb476f5fc5701ec06c23efe3e3529f07ca391e | kernel.org | Patch |
| https://git.kernel.org/stable/c/f13e900599089b10113ceb36013423f0837c6792 | kernel.org | Patch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| NVD-CWE-noinfo | Insufficient Information to Classify Weakness | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 7.0, < 7.1.4 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Aug 17, 2026 | CVE Modified | kernel.org |
| Aug 13, 2026 | Initial Analysis | [email protected] |
| Jul 25, 2026 | New CVE Received | kernel.org |