CVE-2025-39909: debian linux — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters() Patch series "mm/damon: avoid divide-by-zero in DAMON module's parameters application". DAMON's RECLAIM and LRU_SORT modules perform no validation on user-configured parameters during application, which may lead to division-by-zero errors. Avoid the divide-by-zero by adding validation checks when DAMON modules attempt to apply the parameters. This patch (of 2): During the calculation of 'hot_thres' and 'cold_thres', either 'sample_interval' or 'aggr_interval' is used as the divisor, which may lead to division-by-zero errors. Fix it by directly returning -EINVAL when such a case occurs. Additionally, since 'aggr_interval' is already required to be set no smaller than 'sample_interval' in damon_set_attrs(), only the case where 'sample_interval' is zero needs to be checked.

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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	6.0 — 6.1.153
linux	linux_kernel	6.2 — 6.6.107
linux	linux_kernel	6.7 — 6.12.48
linux	linux_kernel	6.13 — 6.16.8
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
debian	debian_linux	All

References

Advisories & Patches

https://git.kernel.org/stable/c/326a4b3750c71af3f3c52399ec4dbe33b6da4c26 https://git.kernel.org/stable/c/711f19dfd783ffb37ca4324388b9c4cb87e71363 https://git.kernel.org/stable/c/74e391f7da7d9d5235a3cca88ee9fc18f720c75b https://git.kernel.org/stable/c/7bb675c9f0257840d33e5d1337d7e3afdd74a6bf https://git.kernel.org/stable/c/af0ae62b935317bed1a1361c8c9579db9d300e70

Other References

https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html

Frequently Asked Questions

What is CVE-2025-39909? +

In the Linux kernel, the following vulnerability has been resolved: mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters() Patch series "mm/damon: avoid divide-by-zero in DAMON module's parameters application". DAMON's RECLAIM and LRU_SORT modules perform no validation on user-configured parameters during application, which may lead to division-by-zero errors. Avoid the divide-by-zero by adding validation checks when DAMON modules attempt to apply the parameters. This patch (of 2): During the calculation of 'hot_thres' and 'cold_thres', either 'sample_interval' or 'aggr_interval' is used as the divisor, which may lead to division-by-zero errors. Fix it by directly returning -EINVAL when such a case occurs. Additionally, since 'aggr_interval' is already required to be set no smaller than 'sample_interval' in damon_set_attrs(), only the case where 'sample_interval' is zero needs to be checked. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-39909? +

CVE-2025-39909 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-2025-39909? +

CVE-2025-39909 affects products from debian, linux, specifically: debian_linux, linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-39909? +

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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