CVE-2026-98648

A flaw was found in the Linux kernel's IBM s390 Ultravisor subsystem. When searching stored secrets on systems holding more than 85 secrets, the kernel incorrectly references the total secret count instead of the number of items stored in the current memory page. A local user can exploit this vulnerability to trigger an out-of-bounds memory read, potentially leading to a Denial of Service (DoS) through a system crash or the disclosure of sensitive kernel memory.

This vulnerability is rated as Moderate impact because exploitation is constrained to local access on the IBM s390x architecture and requires systems utilizing Ultravisor protected virtualization. Architectures other than s390x are unaffected by this flaw. Furthermore, the out-of-bounds condition only occurs when an uncommonly large number of secrets is present in the environment, limiting the overall risk to local service disruption or unprivileged information exposure.

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.