CVE-2023-54092

In the Linux kernel, the following vulnerability has been resolved:

KVM: s390: pv: fix index value of replaced ASCE

The index field of the struct page corresponding to a guest ASCE should be 0. When replacing the ASCE in s390_replace_asce(), the index of the new ASCE should also be set to 0.

Having the wrong index might lead to the wrong addresses being passed around when notifying pte invalidations, and eventually to validity intercepts (VM crash) if the prefix gets unmapped and the notifier gets called with the wrong address.

This vulnerability is rated as Moderate because exploitation requires local access on s390x hardware utilizing KVM with Protected Virtualization (IBM Secure Execution), and the resulting impact is confined to a virtual machine crash. Under specific memory management notifications, improper address space tracking can trigger validity intercepts that terminate the guest rather than enabling host compromise or elevated privileges. Architectures other than IBM Z (s390x) or environments where Protected Virtualization is not active are unaffected.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.