---
id: CVE-2021-44733
title: >-
  A use-after-free exists in drivers/tee/tee_shm.c in the TEE subsystem in the
  Linux kernel through 5.15.11
summary: >-
  A use-after-free exists in drivers/tee/tee_shm.c in the TEE subsystem in the
  Linux kernel through 5.15.11. This occurs because of a race condition in
  tee_shm_get_from_id during an attempt to free a shared memory object.
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-362
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 4.12, < 4.14.261'
  - 'linux_kernel >= 4.15, < 4.19.224'
  - 'linux_kernel >= 4.20, < 5.4.170'
  - 'linux_kernel >= 5.5, < 5.10.89'
  - 'linux_kernel >= 5.11, < 5.15.12'
  - enterprise_linux = 8.0
  - fedora = 35
  - debian_linux = 9.0
  - debian_linux = 10.0
  - debian_linux = 11.0
  - h410c_firmware
  - h300s_firmware
  - h500s_firmware
  - h700s_firmware
  - h300e_firmware
  - h500e_firmware
  - h700e_firmware
  - h410s_firmware
patched:
  - linux_kernel 5.15.12
published: '2021-12-22'
updated: '2026-08-05'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-44733'
references:
  - url: >-
      https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=dfd0743f1d9ea76931510ed150334d571fbab49d
    label: cve@mitre.org
  - url: >-
      https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/drivers/tee/tee_shm.c
    label: cve@mitre.org
  - url: 'https://github.com/pjlantz/optee-qemu/blob/main/README.md'
    label: cve@mitre.org
  - url: 'https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html'
    label: cve@mitre.org
  - url: >-
      https://lore.kernel.org/lkml/20211215092501.1861229-1-jens.wiklander%40linaro.org/
    label: cve@mitre.org
  - url: 'https://security.netapp.com/advisory/ntap-20220114-0003/'
    label: cve@mitre.org
  - url: 'https://www.debian.org/security/2022/dsa-5096'
    label: cve@mitre.org
  - url: >-
      https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=dfd0743f1d9ea76931510ed150334d571fbab49d
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/drivers/tee/tee_shm.c
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/pjlantz/optee-qemu/blob/main/README.md'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lore.kernel.org/lkml/20211215092501.1861229-1-jens.wiklander%40linaro.org/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.netapp.com/advisory/ntap-20220114-0003/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.debian.org/security/2022/dsa-5096'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - exploit-available
epss: 0.00702
epssPercentile: 0.51835
ingestedAt: '2026-08-05T18:50:24.942Z'
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/pjlantz/optee-qemu'
  checkedAt: '2026-09-24T07:52:48.401Z'
exploitAvailable: true
---

## Overview

A use-after-free exists in drivers/tee/tee_shm.c in the TEE subsystem in the Linux kernel through 5.15.11. This occurs because of a race condition in tee_shm_get_from_id during an attempt to free a shared memory object.

## Affected

- `linux_kernel >= 4.12, < 4.14.261`
- `linux_kernel >= 4.15, < 4.19.224`
- `linux_kernel >= 4.20, < 5.4.170`
- `linux_kernel >= 5.5, < 5.10.89`
- `linux_kernel >= 5.11, < 5.15.12`
- `enterprise_linux = 8.0`
- `fedora = 35`
- `debian_linux = 9.0`
- `debian_linux = 10.0`
- `debian_linux = 11.0`
- `h410c_firmware`
- `h300s_firmware`
- `h500s_firmware`
- `h700s_firmware`
- `h300e_firmware`
- `h500e_firmware`
- `h700e_firmware`
- `h410s_firmware`

## Remediation

Upgrade past the affected range:

- `linux_kernel 5.15.12`