---
id: CVE-2026-72105
title: 'dm-log: fix a bitset_size overflow on 32bit machines'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  dm-log: fix a bitset_size overflow on 32bit machines

  Commit c20e36b7631d ("dm log: fix out-of-bounds write due to
  region_count overflow") made sure that region_count c…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 44ab8875ae4a2842bde2d756bed195d375e0debb <
    cdc4ddf9db2cb79f4ab86b1a509b7ac21b0b6cf5
  - >-
    Linux >= defe483e47173768c227532694dc78cb65db5f09 <
    4b0de5a3ac1fd42acb0dc1f80ac5747e3287d723
  - >-
    Linux >= 3ec74da927b4e171a6fc0e77b1188ba4d019af51 <
    567602fa72d57169365cbc589e0b8c3be900636d
  - >-
    Linux >= d4ac87567f86a55c3c92e9a5144dcd943a9772a1 <
    d05e0edfecf5260e6dddd28b2f0cce02bfc6ed7a
  - >-
    Linux >= 12bd5b88e91a02785244ff1d20fb157e96e9cdc8 <
    1c3412b584e1fb6c665ff33ba7259253bc0082cb
  - >-
    Linux >= b455903eed4558982be0811f5b7f44f6bbc4ff57 <
    e0b0163a65758ec3a2361ae1cea407898c27f21e
  - >-
    Linux >= c20e36b7631d83e7535877f08af8b0af72c44b1a <
    79feb87ab2396d49b9b65e4bb815d33cc71cba47
  - >-
    Linux >= c20e36b7631d83e7535877f08af8b0af72c44b1a <
    9743132a41f4d9d0e54c5f2adcb821b04796bab1
  - Linux 4ec8323b9f0764a14d532b1ae9b87f8a9fecb867
  - Linux >= 5.10.258 < 5.10.261
  - Linux >= 5.15.209 < 5.15.212
  - Linux >= 6.1.175 < 6.1.178
  - Linux >= 6.6.141 < 6.6.145
  - Linux >= 6.12.91 < 6.12.97
  - Linux >= 6.18.33 < 6.18.40
  - Linux >= 7.0.10 < 7.1
  - Linux 7.1
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:52:08.599167Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:53:21.465Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-72105'
references:
  - url: 'https://git.kernel.org/stable/c/cdc4ddf9db2cb79f4ab86b1a509b7ac21b0b6cf5'
  - url: 'https://git.kernel.org/stable/c/4b0de5a3ac1fd42acb0dc1f80ac5747e3287d723'
  - url: 'https://git.kernel.org/stable/c/567602fa72d57169365cbc589e0b8c3be900636d'
  - url: 'https://git.kernel.org/stable/c/d05e0edfecf5260e6dddd28b2f0cce02bfc6ed7a'
  - url: 'https://git.kernel.org/stable/c/1c3412b584e1fb6c665ff33ba7259253bc0082cb'
  - url: 'https://git.kernel.org/stable/c/e0b0163a65758ec3a2361ae1cea407898c27f21e'
  - url: 'https://git.kernel.org/stable/c/79feb87ab2396d49b9b65e4bb815d33cc71cba47'
  - url: 'https://git.kernel.org/stable/c/9743132a41f4d9d0e54c5f2adcb821b04796bab1'
tags:
  - cve.org
epss: 0.00169
epssPercentile: 0.05784
ingestedAt: '2026-10-16T17:24:46.879Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

dm-log: fix a bitset_size overflow on 32bit machines

Commit c20e36b7631d ("dm log: fix out-of-bounds write due to
region_count overflow") made sure that region_count could fit in an
unsigned int. But the bitmap memory isn't allocated based on
region_count. It uses bitset_size (a size_t variable). The first step of
calculating bitset_size is to set it to region_count, rounded up to a
multiple of BITS_PER_LONG. If region_size is less than BITS_PER_LONG
smaller than UINT_MAX, it will get rounded up to 2^32. On a 32bit
architecture, this will make bitset_size wrap around to 0 and fail,
despite region_count being valid.

Since bitset_size gets divided by 8, it can hold any valid region_count.
It just needs a special case to handle the rollover. If it is 0, the
value rolled over, and bitset size should be set to the number of bytes
needed to hold 2^32 bits.

## Affected

- `Linux >= 44ab8875ae4a2842bde2d756bed195d375e0debb < cdc4ddf9db2cb79f4ab86b1a509b7ac21b0b6cf5`
- `Linux >= defe483e47173768c227532694dc78cb65db5f09 < 4b0de5a3ac1fd42acb0dc1f80ac5747e3287d723`
- `Linux >= 3ec74da927b4e171a6fc0e77b1188ba4d019af51 < 567602fa72d57169365cbc589e0b8c3be900636d`
- `Linux >= d4ac87567f86a55c3c92e9a5144dcd943a9772a1 < d05e0edfecf5260e6dddd28b2f0cce02bfc6ed7a`
- `Linux >= 12bd5b88e91a02785244ff1d20fb157e96e9cdc8 < 1c3412b584e1fb6c665ff33ba7259253bc0082cb`
- `Linux >= b455903eed4558982be0811f5b7f44f6bbc4ff57 < e0b0163a65758ec3a2361ae1cea407898c27f21e`
- `Linux >= c20e36b7631d83e7535877f08af8b0af72c44b1a < 79feb87ab2396d49b9b65e4bb815d33cc71cba47`
- `Linux >= c20e36b7631d83e7535877f08af8b0af72c44b1a < 9743132a41f4d9d0e54c5f2adcb821b04796bab1`
- `Linux 4ec8323b9f0764a14d532b1ae9b87f8a9fecb867`
- `Linux >= 5.10.258 < 5.10.261`
- `Linux >= 5.15.209 < 5.15.212`
- `Linux >= 6.1.175 < 6.1.178`
- `Linux >= 6.6.141 < 6.6.145`
- `Linux >= 6.12.91 < 6.12.97`
- `Linux >= 6.18.33 < 6.18.40`
- `Linux >= 7.0.10 < 7.1`
- `Linux 7.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.