CVE-2025-21898: linux kernel — Fix

Description

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.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-369 CWE-369

Affected Products

Vendor	Product	Versions
linux	linux_kernel	3.16.83 — 3.17
linux	linux_kernel	4.4.206 — 4.5
linux	linux_kernel	4.9.209 — 4.10
linux	linux_kernel	4.14.163 — 4.15
linux	linux_kernel	4.19.94 — 4.20
linux	linux_kernel	5.4.9 — 5.4.291
linux	linux_kernel	5.5 — 5.10.235
linux	linux_kernel	5.11 — 5.15.179
linux	linux_kernel	5.16 — 6.1.130
linux	linux_kernel	6.2 — 6.6.81
linux	linux_kernel	6.7 — 6.12.18
linux	linux_kernel	6.13 — 6.13.6
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/3d738b53ed6cddb68e68c9874520a4bf846163b5 https://git.kernel.org/stable/c/5b3d32f607f0478b414b16516cf27f9170cf66c8 https://git.kernel.org/stable/c/746cc474a95473591853927b3a9792a2d671155b https://git.kernel.org/stable/c/992775227843c9376773784b8b362add44592ad7 https://git.kernel.org/stable/c/9cdac46fa7e854e587eb5f393fe491b6d7a9bdf6 https://git.kernel.org/stable/c/a1a7eb89ca0b89dc1c326eeee2596f263291aca3 https://git.kernel.org/stable/c/ca381f60a3bb7cfaa618d73ca411610bd7fc3149 https://git.kernel.org/stable/c/f58a3f8e284d0bdf94164a8e61cd4e70d337a1a3

Other References

https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html

Frequently Asked Questions

What is CVE-2025-21898? +

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. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-21898? +

CVE-2025-21898 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-21898? +

CVE-2025-21898 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-21898? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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