CVE-2025-22091 is a vulnerability in the Linux kernel's RDMA mlx5 driver where an integer overflow occurs in the page_size variable. This overflow happens because the variable was originally an unsigned int and could not handle values larger than 31, causing it to wrap to zero when registering large contiguous memory regions (e.g., 4GB). This leads to a kernel warning and potential instability. The issue has been fixed by changing the variable type to unsigned long to properly support larger values.