In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: disallow overlapping input ranges for damon_set_regions()
damon_set_regions() assumes the input ranges are sorted by the address and
don't overlap each other. Hence the assumption was initially to be
explicitly validated. But commit 97d482f4592f ("mm/damon/sysfs: reuse
damon_set_regions() for regions setting") has mistakenly removed the
validation.
This can make DAMON behave in unexpected ways. At the best, the
monitoring results snapshot will just look weird since there will be
overlapping regions. DAMOS will also work weirdly, applying the same
action multiple times for overlapping regions, and make DAMOS quota weird.
More seriously, depending on the setup and regions updates sequence,
negative size regions can be made. It will trigger WARN_ONCE() if the
kernel is built with CONFIG_DAMON_DEBUG_SANITY=y. Depending on the
monitoring results, the negative size region can further trigger division
by zero in damon_merge_two_regions().
Note that some of the consequences including the WARN_ONCE() and the
divide by zero depend on commits that were introduced after the root cause
commit 97d482f4592f ("mm/damon/sysfs: reuse damon_set_regions() for
regions setting").
Fix the problems by checking the assumption and returning an error if
the input ranges don't meet the assumption.
The 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 2026-10-17). 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