CVE-2025-39694

A flaw was found in the Linux kernel's Service Call Control Program (SCLP) driver on s390 architectures. In certain memory configurations, the interrupt tracing mechanism fails to properly validate memory addresses prior to address translation. A local attacker could leverage this flaw to cause improper memory access, leading to a system crash and a denial of service (DoS).

This vulnerability does not affect Red Hat Enterprise Linux versions 9.4 and prior. On s390, the SCLP interrupt tracing path translated the SCCB interrupt address to a virtual address before checking for NULL. If the kernel’s identity mapping does not start at 0, the post-translation pointer is never zero, so the NULL check fails and the code may touch the first page of the identity map, leading to a kernel crash. This issue is specific to the s390 architecture and does not affect other platforms.

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.