CVE Intelligence
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CVE-2026-90004 — mm/damon/core: handle region split failure in apply_min_nr_regions()

In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: handle region split failure in apply_min_nr_regions() damon_apply_min_nr_regions() repeatedly split each region until its size becomes small enough to meet the user-defined low limit of the number of regions. The loop assumes the split operation (damon_split_region_at()) will always succeed and create the new region. But the operation could silently fail for memory allocation failures, for example. If such failure happens and the region was the last region, the linked list-based next region fetching returns invalid pointer. As a result, invalid memory dereference and corruption could happen. Even if the corner case is handled, it imposes stress to the allocator by trying split regions for other targets. Fix the issue by breaking all the loops for any region split failure. This means there could be a min_nr_regions violation. It will only rarely happen since the allocation is arguably too small to fail. Even if it happens, it is only temporal. damon_apply_min_nr_regions() will be called again after the aggregation interval. The user impact of the issue should be minor, since the allocation is arguably too small to fail. But, it could still theoretically happen, and the consequence is very bad. This issue was discovered [1] by Sashiko.

Published Sep 16, 2026 · Updated Oct 19, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

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
  • EPSS 0.2% (30-day exploitation probability)+1

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
0.2%
ahead of 9% of scored CVEs · Oct 19, 2026
Affects
Linux
Linux
CVSS base
—
Score not published yet.

Remediation

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

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

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.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ b1029f29eb1d5fbf07fa8db9b5e7ab6d9813ad67 and < 463ebd63e8ee3d73022a18915ea43320dad8aad7≥ b1029f29eb1d5fbf07fa8db9b5e7ab6d9813ad67 and < c608748607620f331196ed0ba9fe4017892c1457version 7.1 Vulnerable CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 15, 2026 → Oct 19, 2026 · 4 reading(s) · max 0.20%

Detection

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

  • Not enough vector or weakness data: use the affected application’s logs as a starting point.
application logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Record published
    Oct 15, 2026
  • Affected products added · linux/linux
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Received
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Sep 16, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 19, 2026 – Oct 19, 2026
  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

4 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-98866 sched/cache: Introduce task_struct->sched_cache_grp to fix UAF 1d
  • CVE-2026-98867 dm-pcache: bound the logical key offset from persistent memory 1d
  • CVE-2026-98868 dm-pcache: reject a kset that overruns its segment 1d
  • CVE-2026-98856 kprobes: Skip disarmed probes when checking optkprobe overlap 1d
  • CVE-2026-98857 ipvs: bound LBLCR and LBLC cache growth 1d
  • CVE-2026-98858 io_uring: fix task_work add use-after-free with SQPOLL 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 CVSS score published by NVD, the CNA, CISA or GitHub so far.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • 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-2026-90004 is "mm/damon/core: handle region split failure in apply_min_nr_regions()", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.20% estimates the probability of exploitation in 30 days; neither replaces your asset context. 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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