---
id: CVE-2026-64357
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  xfs: fix exchmaps reservation limit check

  xfs_exchmaps_estimate_overhead() adds the bmbt and rmapbt
  overhead to a local resblks variable, but the final UINT_MAX
  check …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  xfs: fix exchmaps reservation limit check

  xfs_exchmaps_estimate_overhead() adds the bmbt and rmapbt
  overhead to a local resblks variable, but the final UINT_MAX
  check …
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 6.10, < 6.12.96'
  - 'linux_kernel >= 6.13, < 6.18.39'
  - 'linux_kernel >= 6.19, < 7.1.4'
patched:
  - linux_kernel 7.1.4
published: '2026-07-25'
updated: '2026-09-04'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64357'
references:
  - url: 'https://git.kernel.org/stable/c/0a5213bbff62b51c7d4999ac8c7e11ea57d00d45'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4707344b0d36d1012c8a1716e20167cd3afdd5f1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a62ef2d13d6e7270dd5e88c6082bf2d0edcd5112'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c597c8580d50127fc1221b5a5b653a94d49e23e3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00122
epssPercentile: 0.01731
ingestedAt: '2026-09-05T13:39:56.757Z'
---

## Overview

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

xfs: fix exchmaps reservation limit check

xfs_exchmaps_estimate_overhead() adds the bmbt and rmapbt
overhead to a local resblks variable, but the final UINT_MAX
check still tests req->resblks.  That is the reservation value
from before the overhead was added.

The computed value is stored back in req->resblks and later passed
to xfs_trans_alloc(), whose block reservation argument is unsigned
int.  Check the computed reservation so the existing limit applies
to the value that will be used.

## Affected

- `linux_kernel >= 6.10, < 6.12.96`
- `linux_kernel >= 6.13, < 6.18.39`
- `linux_kernel >= 6.19, < 7.1.4`

## Remediation

Upgrade past the affected range:

- `linux_kernel 7.1.4`