CVE-2026-74645

mm/damon/lru_sort: error out for >10000 active_mem_bp

Published Aug 22, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

mm/damon/lru_sort: error out for >10000 active_mem_bp

damos_quota_score() can trigger division by zero if the target value is
zero. DAMON_LRU_SORT lets users set the target value for the hot memory
scheme via active_mem_bp parameter. It avoids setting it as the target
value if the parameter value is zero. However, it also sets the cold
memory scheme with a target value that is calculated as '10000 -
active_mem_bp + 2'. Hence, if a user sets active_mem_bp 10002, the cold
memory scheme's quota goal target value can be zero. As a result,
division by zero can be triggered. Fix by returning an error when the
user tries to start DAMON with >10000 active_mem_bp parameter value.

It makes no sense to set active_mem_bp with 10002. It also requires
module parameters write permission to reproduce the issue. That said, the
consequence is quite bad.

One reliable way to reproduce the issue is like below:

# cd /sys/module/damon_lru_sort/parameters
# echo 1000 > wmarks_high
# echo 995 > wmarks_mid
# echo 0 > wmarks_low
# echo 10002 > active_mem_bp
# echo Y > enabled
# dmesg -w
[...]
[ 597.421247] Oops: divide error: 0000 [#1] SMP NOPTI
[ 597.428848] RIP: 0010:damos_quota_score+0x6f/0x480

This issue was discovered [1] by Sashiko.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
History
Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Weaknesses CWE-369
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: mm/damon/lru_sort: error out for >10000 active_mem_bp damos_quota_score() can trigger division by zero if the target value is zero. DAMON_LRU_SORT lets users set the target value for the hot memory scheme via active_mem_bp parameter. It avoids setting it as the target value if the parameter value is zero. However, it also sets the cold memory scheme with a target value that is calculated as '10000 - active_mem_bp + 2'. Hence, if a user sets active_mem_bp 10002, the cold memory scheme's quota goal target value can be zero. As a result, division by zero can be triggered. Fix by returning an error when the user tries to start DAMON with >10000 active_mem_bp parameter value. It makes no sense to set active_mem_bp with 10002. It also requires module parameters write permission to reproduce the issue. That said, the consequence is quite bad. One reliable way to reproduce the issue is like below: # cd /sys/module/damon_lru_sort/parameters # echo 1000 > wmarks_high # echo 995 > wmarks_mid # echo 0 > wmarks_low # echo 10002 > active_mem_bp # echo Y > enabled # dmesg -w [...] [ 597.421247] Oops: divide error: 0000 [#1] SMP NOPTI [ 597.428848] RIP: 0010:damos_quota_score+0x6f/0x480 This issue was discovered [1] by Sashiko.
Title mm/damon/lru_sort: error out for >10000 active_mem_bp
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Aug 22, 2026, 3:32 PM
Reserved
Aug 15, 2026, 5:44 AM
Status
Received
Published
Aug 22, 2026, 4:16 PM
Modified
Oct 14, 2026, 1:10 PM
Severity
Moderate
Public date
Aug 22, 2026, 12:00 AM