CVE-2026-31735 is a high-severity vulnerability in the Linux kernel's iommupt component involving improper invalidation during unmap operations on large mappings. The flaw causes the gather operation to flush only the requested unmap range instead of the entire affected range, leading to a short invalidation. This issue was identified during testing for ARMv8 support. It is likely not triggerable in practice as unmapping large entries is uncommon.