---
id: CVE-2026-72138
title: 'xen/gntdev: fix error handling in ioctl'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  xen/gntdev: fix error handling in ioctl

  When gntdev_ioctl_map_grant_ref() fails to copy the operation result
  back to userspace after successfully adding the mapping to…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 <
    52dc40ef0cfee6ae89b7524967e73f0ba37906d7
  - >-
    Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 <
    1dd9cb98fe228e017fff9efb33862ff38c741b65
  - >-
    Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 <
    6df926130aee6cab9b5d2e5b7862e49ccac348dc
  - >-
    Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 <
    311011f8cc206c5af2877b03e3f627ee1b8fe024
  - >-
    Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 <
    18a693733f7ad004e1ab0466693121ca70cd95dd
  - >-
    Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 <
    16d3ccdabb8dee9be2cdcd6d3f9a125572ec0454
  - >-
    Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 <
    6883269a323609f68f6faa903f8f8ff3d191cec8
  - >-
    Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 <
    45ca1afe2fd14c04e37227e79d3f8455831d8408
  - Linux 2.6.39
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:51:54.267529Z'
published: '2026-08-15'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:55:20.776Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-72138'
references:
  - url: 'https://git.kernel.org/stable/c/52dc40ef0cfee6ae89b7524967e73f0ba37906d7'
  - url: 'https://git.kernel.org/stable/c/1dd9cb98fe228e017fff9efb33862ff38c741b65'
  - url: 'https://git.kernel.org/stable/c/6df926130aee6cab9b5d2e5b7862e49ccac348dc'
  - url: 'https://git.kernel.org/stable/c/311011f8cc206c5af2877b03e3f627ee1b8fe024'
  - url: 'https://git.kernel.org/stable/c/18a693733f7ad004e1ab0466693121ca70cd95dd'
  - url: 'https://git.kernel.org/stable/c/16d3ccdabb8dee9be2cdcd6d3f9a125572ec0454'
  - url: 'https://git.kernel.org/stable/c/6883269a323609f68f6faa903f8f8ff3d191cec8'
  - url: 'https://git.kernel.org/stable/c/45ca1afe2fd14c04e37227e79d3f8455831d8408'
tags:
  - cve.org
epss: 0.00216
epssPercentile: 0.12144
ingestedAt: '2026-11-06T18:00:12.593Z'
---

## Overview

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

xen/gntdev: fix error handling in ioctl

When gntdev_ioctl_map_grant_ref() fails to copy the operation result
back to userspace after successfully adding the mapping to the list,
the error path returns -EFAULT without releasing the reference
acquired by gntdev_alloc_map(). The mapping remains in priv->maps
with a refcount of 1, causing a memory leak and a dangling list
entry.

Additionally, gntdev_add_map() may modify map->index to avoid overlap
with existing mappings. Therefore, the index returned to userspace
must be obtained after gntdev_add_map() completes.

Fix this by holding the mutex across gntdev_add_map(), retrieving
the correct index, and copy_to_user(). If copy_to_user() fails,
remove the mapping from the list and release the reference while
still holding the lock.


Fix these issues by properly handling all error cases.

## Affected

- `Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 < 52dc40ef0cfee6ae89b7524967e73f0ba37906d7`
- `Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 < 1dd9cb98fe228e017fff9efb33862ff38c741b65`
- `Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 < 6df926130aee6cab9b5d2e5b7862e49ccac348dc`
- `Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 < 311011f8cc206c5af2877b03e3f627ee1b8fe024`
- `Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 < 18a693733f7ad004e1ab0466693121ca70cd95dd`
- `Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 < 16d3ccdabb8dee9be2cdcd6d3f9a125572ec0454`
- `Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 < 6883269a323609f68f6faa903f8f8ff3d191cec8`
- `Linux >= 68b025c813c2eb41ff25628e3d4952d5185eb1a4 < 45ca1afe2fd14c04e37227e79d3f8455831d8408`
- `Linux 2.6.39`

## Remediation

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