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Fencer Vulns
high 7.0

CVE-2021-3609 json

.A flaw was found in the CAN BCM networking protocol in the Linux kernel, where a local attacker can abuse a flaw in the CAN subsystem to c…

published 2022-03-03 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-26913

cvss
7.0
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 37%
public exploits
0
none known

Summary

.A flaw was found in the CAN BCM networking protocol in the Linux kernel, where a local attacker can abuse a flaw in the CAN subsystem to corrupt memory, crash the system or escalate privileges. This race condition in net/can/bcm.c in the Linux kernel allows for local privilege escalation to root.

Patch / fix

  • linux linux_kernel 4.4.276, 4.9.276, 4.14.240, 4.19.198, 5.4.132, 5.10.50, 5.12.17, 5.13.2
  • linux Debian 14, Debian 13, Debian 12 5.10.46-1

debian advisories DEBIAN-CVE-2021-3609

  • linux Ubuntu 18.04 LTS 4.15.0-147.151
  • linux Ubuntu 20.04 LTS 5.4.0-77.86
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1106.113
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1051.53
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1046.49
  • linux-gke Ubuntu 20.04 LTS 5.4.0-1046.48
  • linux-hwe Ubuntu 18.04 LTS 5.3.0-75.71
  • linux-kvm Ubuntu 18.04 LTS 4.15.0-1094.96

ubuntu advisories UBUNTU-CVE-2021-3609

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • redhat-virtualization-host rhev hypervisor 4.4 4.4.7-20210804.0.el8_4
  • redhat-virtualization-host-image-update rhev hypervisor 4.4 4.4.7-20210804.0.el8_4
  • kernel-rt RHEL 8 4.18.0-305.12.1.rt7.84.el8_4
  • kernel-rt-kvm RHEL 8 4.18.0-305.12.1.rt7.84.el8_4
  • kernel-rt-core RHEL 8 4.18.0-305.12.1.rt7.84.el8_4
  • kernel-rt-modules RHEL 8 4.18.0-305.12.1.rt7.84.el8_4
  • kernel-rt-debug-kvm RHEL 8 4.18.0-305.12.1.rt7.84.el8_4
  • kernel-rt-debug-core RHEL 8 4.18.0-305.12.1.rt7.84.el8_4

red hat advisories RHSA-2021:3442RHSA-2021:3444RHSA-2021:3235RHSA-2021:3380RHSA-2021:3375RHSA-2021:3363

  • kernel-64kb SLE Module for Basesystem 15 SP3 5.3.18-59.19.1
  • kernel-syms SLE Module for Development Tools 15 SP3 5.3.18-59.19.1
  • kernel-source SLE Module for Development Tools 15 SP3, SLE Module for Basesystem 15 SP3 5.3.18-59.19.1
  • kernel-default SLE Workstation Extension 15 SP3, SLE Module for Legacy 15 SP3, SLE Module for Basesystem 15 SP3 +2 more 5.3.18-59.19.1
  • kernel-preempt SLE Workstation Extension 15 SP3, SLE Module for Development Tools 15 SP3, SLE Module for Basesystem 15 SP3 5.3.18-59.19.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP3 5.3.18-59.19.1
  • kernel-obs-build SLE Module for Development Tools 15 SP3 5.3.18-59.19.1
  • kernel-default-base SLE Module for Basesystem 15 SP3 5.3.18-59.19.1.18.10.1

suse advisories SUSE-SU-2021:14849-1SUSE-SU-2021:2842-1SUSE-SU-2021:2746-1SUSE-SU-2021:2687-1SUSE-SU-2021:2645-1SUSE-SU-2021:2643-1

  • dtb-aarch64 openSUSE Leap 15.3 5.3.18-59.19.1
  • kernel-64kb openSUSE Leap 15.3 5.3.18-59.19.1
  • kernel-syms openSUSE Leap 15.3 5.3.18-59.19.1
  • kernel-obs-qa openSUSE Leap 15.3 5.3.18-59.19.1
  • kernel-source openSUSE Leap 15.3 5.3.18-59.19.1
  • kernel-default openSUSE Leap 15.3 5.3.18-59.19.1
  • kernel-preempt openSUSE Leap 15.3 5.3.18-59.19.1
  • kernel-kvmsmall openSUSE Leap 15.3 5.3.18-59.19.1

opensuse advisories openSUSE-SU-2021:2687-1openSUSE-SU-2021:2645-1openSUSE-SU-2021:1076-1openSUSE-SU-2021:2427-1

  • kernel-rt Rocky Linux 8 4.18.0-305.12.1.rt7.84.el8_4
  • kernel Rocky Linux 8 4.18.0-305.12.1.el8_4

rocky linux advisories RLSA-2021:3088RLSA-2021:3057

  • linux Arch Linux 5.13.4.arch1-1
  • linux-zen Arch Linux 5.13.4.zen1-1
  • linux-hardened Arch Linux 5.12.19.hardened1-1
  • linux-lts Arch Linux 5.10.52-1

arch linux advisories AVG-2181AVG-2182AVG-2183AVG-2184

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-3609 updated cvss 7.0

kernel: race condition in net/can/bcm.c leads to local privilege escalation

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat CodeReady Linux Builder (v. 8) kernel-debuginfo-common-x86_64 4.18.0-305.12.1.el8_4, kernel-debuginfo-common-aarch64 4.18.0-305.12.1.el8_4, kernel-debuginfo-common-ppc64le 4.18.0-305.12.1.el8_4
    fixed: vendor fix RHSA-2021:3057
  • Red Hat CodeReady Linux Builder EUS (v. 8.1) kernel-debuginfo-common-x86_64 4.18.0-147.54.2.el8_1, kernel-debuginfo-common-aarch64 4.18.0-147.54.2.el8_1, kernel-debuginfo-common-ppc64le 4.18.0-147.54.2.el8_1
    fixed: vendor fix RHSA-2021:3444
  • Red Hat CodeReady Linux Builder EUS (v. 8.2) kernel-debuginfo-common-x86_64 4.18.0-193.64.1.el8_2, kernel-debuginfo-common-aarch64 4.18.0-193.64.1.el8_2, kernel-debuginfo-common-ppc64le 4.18.0-193.64.1.el8_2
    fixed: vendor fix RHSA-2021:3363
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-305.12.1.el8_4, kernel 4.18.0-305.12.1.el8_4, bpftool 4.18.0-305.12.1.el8_4, kpatch-patch-4_18_0-305 1-4.el8, kernel-core 4.18.0-305.12.1.el8_4, kernel-tools 4.18.0-305.12.1.el8_4, +19 more
    fixed: vendor fix RHSA-2021:3057
  • Red Hat Enterprise Linux BaseOS EUS (v. 8.1) perf 4.18.0-147.54.2.el8_1, kernel 4.18.0-147.54.2.el8_1, bpftool 4.18.0-147.54.2.el8_1, kernel-core 4.18.0-147.54.2.el8_1, kernel-tools 4.18.0-147.54.2.el8_1, python3-perf 4.18.0-147.54.2.el8_1, +25 more
    fixed: vendor fix RHSA-2021:3444
  • Red Hat Enterprise Linux BaseOS EUS (v. 8.2) perf 4.18.0-193.64.1.el8_2, kernel 4.18.0-193.64.1.el8_2, bpftool 4.18.0-193.64.1.el8_2, kernel-core 4.18.0-193.64.1.el8_2, kernel-tools 4.18.0-193.64.1.el8_2, python3-perf 4.18.0-193.64.1.el8_2, +26 more
    fixed: vendor fix RHSA-2021:3363
  • Red Hat Enterprise Linux Real Time (v. 8) kernel-rt 4.18.0-305.12.1.rt7.84.el8_4, kernel-rt-core 4.18.0-305.12.1.rt7.84.el8_4, kernel-rt-modules 4.18.0-305.12.1.rt7.84.el8_4, kernel-rt-debug-core 4.18.0-305.12.1.rt7.84.el8_4, kernel-rt-debug-modules 4.18.0-305.12.1.rt7.84.el8_4, kernel-rt-modules-extra 4.18.0-305.12.1.rt7.84.el8_4, +2 more
    fixed: vendor fix RHSA-2021:3088
show 5 more
  • Red Hat Enterprise Linux Real Time EUS (v. 8.2) kernel-rt 4.18.0-193.64.1.rt13.115.el8_2, kernel-rt-core 4.18.0-193.64.1.rt13.115.el8_2, kernel-rt-modules 4.18.0-193.64.1.rt13.115.el8_2, kernel-rt-debug-core 4.18.0-193.64.1.rt13.115.el8_2, kernel-rt-debug-modules 4.18.0-193.64.1.rt13.115.el8_2, kernel-rt-modules-extra 4.18.0-193.64.1.rt13.115.el8_2, +2 more
    fixed: vendor fix RHSA-2021:3375
  • Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt 4.18.0-305.12.1.rt7.84.el8_4, kernel-rt-kvm 4.18.0-305.12.1.rt7.84.el8_4, kernel-rt-core 4.18.0-305.12.1.rt7.84.el8_4, kernel-rt-modules 4.18.0-305.12.1.rt7.84.el8_4, kernel-rt-debug-kvm 4.18.0-305.12.1.rt7.84.el8_4, kernel-rt-debug-core 4.18.0-305.12.1.rt7.84.el8_4, +4 more
    fixed: vendor fix RHSA-2021:3088
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 8.2) kernel-rt 4.18.0-193.64.1.rt13.115.el8_2, kernel-rt-kvm 4.18.0-193.64.1.rt13.115.el8_2, kernel-rt-core 4.18.0-193.64.1.rt13.115.el8_2, kernel-rt-modules 4.18.0-193.64.1.rt13.115.el8_2, kernel-rt-debug-kvm 4.18.0-193.64.1.rt13.115.el8_2, kernel-rt-debug-core 4.18.0-193.64.1.rt13.115.el8_2, +4 more
    fixed: vendor fix RHSA-2021:3375
  • Red Hat Virtualization 4 Hypervisor for RHEL 8 redhat-virtualization-host 4.4.7-20210804.0.el8_4, redhat-virtualization-host-image-update 4.4.7-20210804.0.el8_4
    fixed: vendor fix RHSA-2021:3235
  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more Red Hat RHEL 8-based RHEV-H for RHEV 4 (build requirements) imgbased 1.2.23-1.el8ev, python3-imgbased 1.2.23-1.el8ev, redhat-release-virtualization-host 4.4.7-4.el8ev, redhat-virtualization-host-image-update-placeholder 4.4.7-4.el8ev
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/nrb547/kernel-exploitation/blob/main/cve-2021-3609/cve-2021-3609.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.9 AV:L/AC:M/Au:N/C:C/I:C/A:C

Affected products

  • n/a kernel

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.