CVE-2026-63940

Name	CVE-2026-63940
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
linux (PTS)	bullseye	5.10.223-1	fixed
	bullseye (security)	5.10.259-1	fixed
	bookworm	6.1.176-1	vulnerable
	bookworm (security)	6.1.177-1	vulnerable
	trixie	6.12.94-1	vulnerable
	trixie (security)	6.12.95-1	fixed
	forky	7.1.3-1	fixed
	sid	7.1.4-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version
linux	source	bullseye	(not affected)
linux	source	trixie	6.12.95-1
linux	source	(unstable)	7.0.12-1

[bullseye] - linux <not-affected> (Vulnerable code not present)
https://git.kernel.org/linus/3988bd2723de407ae90fa7a6f6029b4e60238c58 (7.1-rc6)