---
id: CVE-2021-34693
title: >-
  net/can/bcm.c in the Linux kernel through 5.12.10 allows local users to obtain
  sensitive information from kernel stack memory because parts of a data
  structure are uninitialized.
summary: >-
  net/can/bcm.c in the Linux kernel through 5.12.10 allows local users to obtain
  sensitive information from kernel stack memory because parts of a data
  structure are uninitialized.
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-909
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 2.6.25, <= 5.12.10'
  - debian_linux = 9.0
  - debian_linux = 10.0
published: '2021-06-14'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:17:36.107'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-34693'
references:
  - url: 'http://www.openwall.com/lists/oss-security/2021/06/15/1'
    label: cve@mitre.org
  - url: >-
      https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=5e87ddbe3942e27e939bdc02deb8579b0cbd8ecc
    label: cve@mitre.org
  - url: 'https://lists.debian.org/debian-lts-announce/2021/07/msg00014.html'
    label: cve@mitre.org
  - url: 'https://lists.debian.org/debian-lts-announce/2021/07/msg00015.html'
    label: cve@mitre.org
  - url: 'https://lists.debian.org/debian-lts-announce/2021/07/msg00016.html'
    label: cve@mitre.org
  - url: >-
      https://lore.kernel.org/netdev/trinity-87eaea25-2a7d-4aa9-92a5-269b822e5d95-1623609211076%403c-app-gmx-bs04/T/
    label: cve@mitre.org
  - url: 'https://www.debian.org/security/2021/dsa-4941'
    label: cve@mitre.org
  - url: 'http://www.openwall.com/lists/oss-security/2021/06/15/1'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=5e87ddbe3942e27e939bdc02deb8579b0cbd8ecc
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2021/07/msg00014.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2021/07/msg00015.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2021/07/msg00016.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lore.kernel.org/netdev/trinity-87eaea25-2a7d-4aa9-92a5-269b822e5d95-1623609211076%403c-app-gmx-bs04/T/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.debian.org/security/2021/dsa-4941'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00472
epssPercentile: 0.38968
ingestedAt: '2026-10-08T22:11:53.736Z'
---

## Overview

net/can/bcm.c in the Linux kernel through 5.12.10 allows local users to obtain sensitive information from kernel stack memory because parts of a data structure are uninitialized.

## Affected

- `linux_kernel >= 2.6.25, <= 5.12.10`
- `debian_linux = 9.0`
- `debian_linux = 10.0`

## Remediation

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