CVE-2026-64369

A flaw was found in the Linux kernel, specifically within the s390 architecture. When the system attempts to read unaligned data that spans across memory pages, it can trigger exceptions. For memory pages designated for secure execution by the Ultravisor, the exception handling mechanism does not correctly resolve these issues. This improper handling can lead to a continuous loop of exceptions, ultimately causing a Denial of Service (DoS) where the system becomes unresponsive.

This vulnerability is rated as having a Moderate impact because exploitation is restricted to the s390x architecture in environments utilizing IBM Secure Execution, requiring local user access to trigger. On affected deployments, an unhandled exception loop can result in a denial of service by causing the host system to hang, while confidentiality and integrity remain unaffected. Non-s390x architectures and environments that do not run Ultravisor-protected guests are not vulnerable to this issue.

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.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.