[SRU][J][PATCH 0/1] CVE-2026-63940

[Rickey Castillo]

https://ubuntu.com/security/CVE-2026-63940

[ Impact ]

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.

[ Fix ]

3b6035bc6bff ("KVM: SEV: Ignore Port I/O requests of length '0'")
Applied cleany from linux-6.12.y

[ Test Plan ]

Build and boot tested.

[ Where Problems Could Occur ]

Running legacy, poorly optimized, or custom guest operating systems that repeatedly 
trigger these invalid zero-length operations, the host system logs could get 
heavily flooded

Sean Christopherson (1):
  KVM: SEV: Ignore Port I/O requests of length '0'

 arch/x86/kvm/svm/sev.c | 8 ++++++++
 1 file changed, 8 insertions(+)

-- 
2.53.0