A race condition exists between the dat_entry_walk() and large_crste_to_phys() functions in the KVM s390 implementation of the Linux kernel. If a large page is split concurrently, the code may dereference a stale page table entry and attempt to write a storage key to an invalid absolute address, leading to a crash of the kernel. The crash results in a system halt or reboot, effectively denying service for the affected node. No arbitrary code execution or data compromise is exposed by this flaw, but the impact on service availability is significant.

The vulnerability affects Linux kernel implementations running on the s390 architecture (IBM Z). No specific version range is provided, but the issue was fixed by recent kernel commits. Any systems that have not applied this patch and are running older kernel releases on s390 are potentially vulnerable.

The CVSS score of 4.7 places the vulnerability in the low‑to‑medium range, indicating a modest severity. The EPSS score of less than 1 % suggests a very low likelihood of exploitation. The flaw is not listed in the CISA KEV catalog. Exploitation requires a concurrent page‑split event that can be triggered by code executing in the context of KVM. Achieving the race within the kernel would most likely need at least privileged or local access, and remote exploitation is unlikely. The main consequence of a successful exploit is a kernel crash that results in a denial of service for the host system.