CVE-2026-64285

Summary

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@]

Affected Software

VendorProductVersion RangeStatus
LinuxLinux2a62345b30529e488beb6a1220577b3495933724 < dcdb476f5fc5701ec06c23efe3e3529f07ca391eaffected
LinuxLinux2a62345b30529e488beb6a1220577b3495933724 < f13e900599089b10113ceb36013423f0837c6792affected
LinuxLinux7.0affected
LinuxLinux0 < 7.0unaffected
LinuxLinux7.1.4 <= 7.1.*unaffected
LinuxLinux7.2-rc1 <= *unaffected

Weaknesses

References