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.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
- EG Severity
- Not assessed: no CVSS publishedA missing CVSS is not a severity of zero.
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- No SSVC decision: EchelonGraph has not assessed this CVECISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the BOD 26-04 block below.
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it