KVM: SEV: Ignore Port I/O requests of length '0'
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.
02 / AFFECTED SOFTWARE
Affected packages
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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.
05 / REFERENCES
Further evidence
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- https://git.kernel.org/stable/c/2254972d4d69e279ba4e87bf0968eb08ad0d3c92
- https://git.kernel.org/stable/c/3988bd2723de407ae90fa7a6f6029b4e60238c58
- https://git.kernel.org/stable/c/3b6035bc6bff20e89752ce4358bc4c9a9d5883f2
- https://git.kernel.org/stable/c/c30cde934c7813b4e3069765dac64ce3d31e34f2
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63940.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-63940