CVE-2026-63940 Details
Description
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.
A vulnerability in the Linux kernel's KVM (Kernel-based Virtual Machine) SEV (Secure Encrypted Virtualization) module has been addressed. This vulnerability involved Port I/O requests with a length of zero, which could cause issues when setting up the software scratch area. The kernel now explicitly ignores such requests, preventing potential underflows and allowing for warnings when the scratch area is configured with a length of zero.
Users can upgrade to the latest version of the Linux kernel where this vulnerability has been fixed. The patch is included in the official Linux stable releases.
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.
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Weakness Enumeration
No weakness enumeration is available for this CVE.
Affected Products
No affected product data is available for this CVE.
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 20, 2026 | CVE Modified | kernel.org |
| Jul 19, 2026 | New CVE Received | kernel.org |