Medium

CVE-2025-39909 — mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters()

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.

Published Oct 1, 2025 · Updated Oct 19, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Debian

Debian Linux and 2 more

CVSS base

5.5

Medium · 1 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Debian Debian Linux, Linux Linux, Linux Linux Kernel).
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Debian	Debian Linux	version 11.0	Vulnerable	NIST National Vulnerability Database
Linux	Linux	≥ 40e983cca9274e177bd5b9379299b44d9536ac68 and < 74e391f7da7d9d5235a3cca88ee9fc18f720c75b≥ 40e983cca9274e177bd5b9379299b44d9536ac68 and < 7bb675c9f0257840d33e5d1337d7e3afdd74a6bf≥ 40e983cca9274e177bd5b9379299b44d9536ac68 and < af0ae62b935317bed1a1361c8c9579db9d300e70≥ 40e983cca9274e177bd5b9379299b44d9536ac68 and < 326a4b3750c71af3f3c52399ec4dbe33b6da4c26≥ 40e983cca9274e177bd5b9379299b44d9536ac68 and < 711f19dfd783ffb37ca4324388b9c4cb87e71363version 6.0	Vulnerable	CVE Program (cve.org) e CISA ADP
Linux	Linux Kernel	≥ 6.0 and < 6.1.153≥ 6.2 and < 6.6.107≥ 6.7 and < 6.12.48≥ 6.13 and < 6.16.8version 6.17-rc1version 6.17-rc2version 6.17-rc3version 6.17-rc4 and 1 more version 6.17-rc5	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
5.5	CVSS 3.1	Medium	1.8	3.6	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-369

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.

endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · linux/linux
Oct 19, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 19, 2026
Fix documented
Oct 19, 2026 · NIST National Vulnerability Database
CVSS changed · 5.5
Oct 19, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 19, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 19, 2026 · NIST National Vulnerability Database
2025
CVE published
Oct 1, 2025 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 19, 2026 – Oct 19, 2026

References

6 on the record

git.kernel.org/stable/c/af0ae62b935317bed1a1361c8c9579db9d300e70
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/74e391f7da7d9d5235a3cca88ee9fc18f720c75b
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/326a4b3750c71af3f3c52399ec4dbe33b6da4c26
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/711f19dfd783ffb37ca4324388b9c4cb87e71363
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/7bb675c9f0257840d33e5d1337d7e3afdd74a6bf
Patch, NIST National Vulnerability Database
lists.debian.org/debian-lts-announce/2025/10/msg00008.html
Third Party Advisory, NIST National Vulnerability Database

Elsewhere on this site

Debian
every CVE for this vendor

CWE-369
other pages naming this weakness

Related CVEs (same products)

Unknown CVE-2026-98868 dm-pcache: reject a kset that overruns its segment 1d
Unknown CVE-2026-98866 sched/cache: Introduce task_struct->sched_cache_grp to fix UAF 1d
Unknown CVE-2026-98867 dm-pcache: bound the logical key offset from persistent memory 1d
Unknown CVE-2026-98865 sched_ext: Don't run ops.dequeue() with a DSQ lock held 1d
Unknown CVE-2026-98864 sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task 1d
Unknown CVE-2026-98863 KVM: x86: Re-pend GET_NESTED_STATE_PAGES if getting said pages fails 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No CISA SSVC assessment.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-39909 is "mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters()", rated Medium. It affects Debian Linux (Debian); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.5 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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