CVE-2025-21898: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: ftrace: Avoid potential division by zero in function_stat_show() Check whether denominator expression x * (x - 1) * 1000 mod {2^32, 2^64} produce zero and skip stddev computation in that case. For now don't care about rec->counter * rec->counter overflow because rec->time * rec->time overflow will likely happen earlier.

Affected products

• Linux Linux Kernel: from 3.16.83, before 3.17 (fixed in 3.17); from 4.4.206, before 4.5 (fixed in 4.5); from 4.9.209, before 4.10 (fixed in 4.10); from 4.14.163, before 4.15 (fixed in 4.15); from 4.19.94, before 4.20 (fixed in 4.20); from 5.4.9, before 5.4.291 (fixed in 5.4.291); …

Published 2025-04-01. Last modified 2026-06-17.