CVE-2026-46107

Local storage disruption via metadata refcount underflow

Published May 28, 2026 · Updated May 28, 2026

Reference-count underflow in Linux Kernel dm-thin allows local users to cause metadata errors during B-tree rebalancing. In rebalance_children, copying entries from a shared single-entry child creates duplicate grandchild pointers without increasing the grandchildren's reference counts. Reaching the flaw requires local low privileges; the advisory documents space-map decrement errors but does not substantiate cross-volume disclosure or corruption.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reference-count underflow in Linux Kernel dm-thin allows local users to cause metadata errors during B-tree rebalancing. In rebalance_children, copying entries from a shared single-entry child creates duplicate grandchild pointers without increasing the grandchildren's reference counts. Reaching the flaw requires local low privileges; the advisory documents space-map decrement errors but does not substantiate cross-volume disclosure or corruption.

The record

CVE
CVE-2026-46107
Published
May 28, 2026
Updated
May 28, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-911, CWE-191, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 28, 2026CVE publishedPublication date reported by the CVE source.
  2. May 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.2
  2. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <09a65adc7d8bbfce06392cb6d375468e2728ead5
  3. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <12161e03d33afce781f68fa11cc6060538862fad
  4. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <323d252a4a378834e4fe68298ca61cfc5dd3a460
  5. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <5ec0debbcfd43596e32c1239e993de06a704e04c
  6. Affected versionversion=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <85311a585a26640760cd0f3349ab9f2905691044

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.2; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <09a65adc7d8bbfce06392cb6d375468e2728ead5; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <12161e03d33afce781f68fa11cc6060538862fad; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <323d252a4a378834e4fe68298ca61cfc5dd3a460; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <5ec0debbcfd43596e32c1239e993de06a704e04c; version=3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 <85311a585a26640760cd0f3349ab9f2905691044

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.1Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-911Improper Update of Reference Count
CWE-191Integer Underflow (Wrap or Wraparound)
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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