Linux Kernel Vulnerability in KVM s390 PCI Handling

CVE-2026-68454

What is CVE-2026-68454?

A vulnerability exists in the Linux kernel regarding the KVM subsystem when handling PCI interrupts for the s390 architecture. Specifically, if a guest attempts to register Interrupt Request Lines (IRQs) without a specified summary bit, the subsequent Guest Adapter Information Table Entry (GAITE) erroneously stores a virtual address instead of a zero value for the guest's Adapter Interrupt Summary Bit (AISB) location. This oversight can lead to unexpected behavior and potential system instability, highlighting the importance of proper IRQ management and validation within virtualized environments.

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