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NVD / CVE Program· CNA Linux

CVE-2026-89796: mm/damon/core: avoid infinite kdamond_merge_regions() internal loop

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.22% (FIRST EPSS).
  • Fixed version: Linux Linux 123e4619ab6c8ab1c4cb1d7a58311a2af13929cd, 407da1dd7f48e5ba22ceb8834f6923390632d025, 5.15.222; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 123e4619ab6c8ab1c4cb1d7a58311a2af13929cd, 407da1dd7f48e5ba22ceb8834f6923390632d025, 5.15.222; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: avoid infinite kdamond_merge_regions() internal loop Patch series "mm/damon: unurgent fixes for infinite loop, NULL de-ref and races", v1.1. Sashiko found a few issues in DAMON that could cause infinite loop, NULL dereference and monitoring results degradation. The first two sounds scary but the infinite loop happens only under unreasonable user setup. The NULL dereference is only in a unit test. Monitoring results degradation is trivial since it is only best-effort, and those happens from only unlikely races. Still those are bugs that better to fix if possible. Fix those. This patch (of 6): Due to online parameter update like events, the number of DAMON regions could be higher than the user-set upper limit. kdamond_merge_regions() repeats merge regions until the number meets the limit, while doubling the merge threshold up to the theoretical maximum threshold. It is tried only up to the theoretical maximum threshold because even the aggressive merging can fail from reducing the number of regions under the user-defined upper limit. For example, there could be many user-defined non-contiguous regions that cannot be merged. The threshold based loop break condition is evaluated by comparing the threshold for the next merging try against the theoretical maximum threshold. If max_thres is larger than UINT_MAX / 2, doubling the threshold could make it overflow, and bypass the loop break condition. In the case, if the number of regions cannot be reduced under the upper limit like explained above, the loop will run infinitely. Prevent the case by doing the break condition check before doubling the threshold. Also, prevent the threshold exceeding the maximum threshold, as it could overflow and apply the wrong merge threshold. This issue is unlikely to occur in real world, since having the max_thres higher than UINT_MAX / 2 require unrealistically large aggregation intervals compared to the sampling interval. Also, it requires an unrealistically large number of uncontiguous regions setup. Nonetheless, the consequence is bad and the fix is simple. The issue was discovered [1] by Sashiko.

—No exploit Fix available
Published
Sep 16, 2026
Updated
Oct 19, 2026
EPSS
0.2% · 12th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • f2bd3184b6aeca6a497394b558337246e09fc02d, 6.10affected
    • 1e865019cef354a5f0314491b4b4fc9f9a613642 and later · before 407da1dd7f48e5ba22ceb8834f6923390632d025affected · git
    • d7eda72e59bbf3ed592db7ff0fd8c246c73149a8 and later · before 65edd8b3a88278c9f8e5c7d8c15d4f296ce35078affected · git
    • 11078e2d11465518a9e85096bd28f8cd5fa1ea41 and later · before 5b0953f86d65855dc901050f40bbe6da0475d198affected · git
    • 310d6c15e9104c99d5d9d0ff8e5383a79da7d5e6 and later · before 769c16699c89811386eb003c8fd9dcb8d405b316affected · git
    • 310d6c15e9104c99d5d9d0ff8e5383a79da7d5e6 and later · before 50a7a5aec1aa43efc297fd4377c1cbdc7d15620daffected · git
    • 310d6c15e9104c99d5d9d0ff8e5383a79da7d5e6 and later · before 8a96a06e04d210845be5d9581c0e9e338947e8f8affected · git
    • 310d6c15e9104c99d5d9d0ff8e5383a79da7d5e6 and later · before 123e4619ab6c8ab1c4cb1d7a58311a2af13929cdaffected · git
    • 5.15.164 and later · before 5.15.222affected · semver
    • 6.1.101 and later · before 6.1.189affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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Published before and after this one in the same product

  • ← EarlierCVE-2026-89794Sep 16, 2026 · ksmbd: zero pipe read compound padding
    0Monitor
  • ← EarlierCVE-2026-89795Sep 16, 2026 · PCI: Allow per function PCI slots to fix slot reset on s390
    33Monitor
  • Later →CVE-2026-89797Sep 16, 2026 · power: supply: ab8500_fg: fix use-after-free on remove
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux123e4619ab6c8ab1c4cb1d7a58311a2af13929cdVendor (CNA)
Linux Linux407da1dd7f48e5ba22ceb8834f6923390632d025Vendor (CNA)
Linux Linux5.15.222Vendor (CNA)
Linux Linux50a7a5aec1aa43efc297fd4377c1cbdc7d15620dVendor (CNA)
Linux Linux5b0953f86d65855dc901050f40bbe6da0475d198Vendor (CNA)
Linux Linux6.1.189Vendor (CNA)
Linux Linux6.10Vendor (CNA)
Linux Linux6.6.158Vendor (CNA)
Linux Linux65edd8b3a88278c9f8e5c7d8c15d4f296ce35078Vendor (CNA)
Linux Linux769c16699c89811386eb003c8fd9dcb8d405b316Vendor (CNA)
Linux Linux8a96a06e04d210845be5d9581c0e9e338947e8f8Vendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.0—Microsoft (MSRC)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.06.6.158.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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