by Kastro
Paper/Archive/CVE-2026-63940

CVE-2026-63940

Linux Linux — KVM: SEV: Ignore Port I/O requests of length '0'

EPSS 0.2%CVSS 9.3
critical.is priorityof 100
30
CVSS 9.3 (CNA)9.3 / 10 × 3027.9Not in CISA KEV+300.0EPSS percentile 8.2.082 × 201.6No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Ignore Port I/O requests of length '0' Explicitly ignore Port I/O requests of length '0' (or count '0'), so that setting up the software scratch area (and other code) doesn't have to worry about underflowing the length, and to allow for WARNing on trying to configure the scratch area with len==0.

Affected

ProductAffectedFixed inSource
Linux291bd20d5d88814a73d43b55b9428feab2f28094 – < bbd3a27e4f99fdcad82d12d79c04a95dff1ff70bbbd3a27e4f99fdcad82d12d79c04a95dff1ff70bCNA
Linux291bd20d5d88814a73d43b55b9428feab2f28094 – < 3b6035bc6bff20e89752ce4358bc4c9a9d5883f23b6035bc6bff20e89752ce4358bc4c9a9d5883f2CNA
Linux291bd20d5d88814a73d43b55b9428feab2f28094 – < 2254972d4d69e279ba4e87bf0968eb08ad0d3c922254972d4d69e279ba4e87bf0968eb08ad0d3c92CNA
Linux291bd20d5d88814a73d43b55b9428feab2f28094 – < c30cde934c7813b4e3069765dac64ce3d31e34f2c30cde934c7813b4e3069765dac64ce3d31e34f2CNA
Linux291bd20d5d88814a73d43b55b9428feab2f28094 – < 3988bd2723de407ae90fa7a6f6029b4e60238c583988bd2723de407ae90fa7a6f6029b4e60238c58CNA
Linux5.11–CNA

Scores by source

Linux (CNA)9.3CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

refgit.kernel.org/stable/c/bbd3a27e4f99fdcad82d12d79c04a95dff1ff70brefgit.kernel.org/stable/c/3b6035bc6bff20e89752ce4358bc4c9a9d5883f2refgit.kernel.org/stable/c/2254972d4d69e279ba4e87bf0968eb08ad0d3c92refgit.kernel.org/stable/c/c30cde934c7813b4e3069765dac64ce3d31e34f2refgit.kernel.org/stable/c/3988bd2723de407ae90fa7a6f6029b4e60238c58