The fork implementation in the Linux kernel before 4.5 on s390 platforms mishandles the case of four page-table levels, which allows local users to cause a denial of service (system crash) or possibly have unspecified other impact via a crafted application, related to arch/s390/include/asm/mmu_context.h and arch/s390/include/asm/pgalloc.h.
Severity
CVSS 3.1
7.8 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
0.6% chance of exploitation in the next 30 days; higher than 46% of CVEs (scores of 2026-10-31)