Vulnerability in Linux Kernel Affecting KVM on S390 Architecture

CVE-2026-80891

What is CVE-2026-80891?

A vulnerability has been identified in the Linux kernel's KVM subsystem for the s390 architecture. The flaw centers around improper validation of AIBV and AISB structures prior to pinning guest memory pages. Specifically, if the AIBV, which is a bit vector for MSI-X vectors, exceeds a single page boundary, the request should be rejected to prevent unsafe memory pinning. Additionally, any request with an unaligned AISB address, contrary to the requirement for doubleword alignment, is also rejected. This mechanism is crucial for maintaining the integrity and security of virtualized environments running on the s390 architecture, ensuring that memory operations remain within safe operational limits.

References