CVE-2025-68179

A flaw was found in the Linux kernel on the s390 architecture. A local user with low privileges could trigger a vulnerability by enabling ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP. This issue arises because kernel page table entries are modified without properly flushing the Translation Lookaside Buffer (TLB), which can lead to system crashes and potential data corruption. This could result in a denial of service.

A moderate severity flaw was found in the Linux kernel on the s390 (IBM Z) architecture as shipped in Red Hat Enterprise Linux 9 and Red Hat Enterprise Linux 10 (kernel and kernel-rt). When HugeTLB Vmemmap Optimization (HVO) is enabled, kernel page table entries are modified without properly flushing the corresponding TLB entries; on s390, replacing a valid page table entry with another valid entry without first going through an invalid entry violates the s390 architecture requirements and may lead to random crashes and data corruption. A local user with low privileges could trigger this flaw, resulting in a denial of service and potential data corruption. Red Hat Enterprise Linux 6, 7, and 8, and Red Hat In-Vehicle OS 1.1 are not affected because the vulnerable code is not present in those products. The fix is currently deferred for the affected RHEL 9 and RHEL 10 streams; because the issue is specific to the s390 architecture and only manifests when HugeTLB Vmemmap Optimization is in use, the residual risk is limited to denial of service and potential data corruption on s390 systems using that feature. Red Hat assesses the impact of this flaw as Moderate rather than the upstream Important severity, as the primary consequence is loss of availability (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).

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 do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.