CVE-2026-43486

A flaw was found in the Linux kernel. The contpte_ptep_set_access_flags() function, responsible for managing contiguous page table entries (CONT PTEs) on ARM64 architectures, incorrectly determines when an access flag update is a no-op. This can occur when a sibling page table entry's dirty bit causes the target entry to appear already updated. Consequently, page-table walkers, such as those in a System Memory Management Unit (SMMU) or Address Translation Services (ATS), can enter an infinite fault loop, leading to a system crash and a Denial of Service (DoS).

Red Hat has evaluated this issue as having a Moderate severity impact because exploitation is restricted to local authenticated users on ARM64 systems and leads solely to a denial of service through an infinite fault loop, without compromising data confidentiality or system integrity. The flaw is confined to ARM64 hardware configurations employing contiguous memory mappings and does not affect Red Hat Enterprise Linux releases prior to version 10, as the vulnerable code is not present in earlier kernel versions.

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.