CVE-2025-21898 is a medium severity vulnerability in the Linux kernel's ftrace subsystem. It involves a potential division by zero error in the function_stat_show() function. The issue arises when a denominator expression involving multiplication and modulo operations results in zero, which could cause a crash or denial of service. The vulnerability does not impact confidentiality or integrity but affects availability. No known exploits are reported in the wild. No specific affected versions are provided in the data.