CVE-2026-64285: KVM: SEV: Pin source page for write when adding CPUID data for SNP guest
Vulnerability summary
CVE-2026-64285 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.14% chance of exploitation in the next 30 days, higher than 3.6% of scored vulnerabilities.
Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 12 · Related 12Timeline
- 25-07-2026PublishedVulnerability first disclosed.
- 17-08-2026Last modifiedVulnerability information updated.
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@]
CVSS metrics
3 scores · 3 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.14%
Chance of exploitation in the next 30 days
Percentile
4%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.14% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu112 products
- linux< 7.0.0-31.31
- linux-allwinner-5.19All versions (No fix recorded)
- linux-aws< 7.0.0-1012.12
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 2a62345b30529e488beb6a1220577b3495933724, < dcdb476f5fc5701ec06c23efe3e3529f07ca391e | ≥ 2a62345b30529e488beb6a1220577b3495933724, < f13e900599089b10113ceb36013423f0837c6792 | 7.0
- linux_kernel≥ 7.0, < 7.1.4
Debian1 product
- linux< 7.1.4-1
3 vendors · 115 products
