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Fencer Vulns
high 7.8

CVE-2021-47459 json

can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv

published 2024-05-22 2 y ago modified 2026-08-05 3 mo ago also EUVD-2021-34464

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 13%
public exploits
0
none known

Summary

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

can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv

It will trigger UAF for rx_kref of j1939_priv as following.

cpu0 cpu1 j1939_sk_bind(socket0, ndev0, ...) j1939_netdev_start j1939_sk_bind(socket1, ndev0, ...) j1939_netdev_start j1939_priv_set j1939_priv_get_by_ndev_locked j1939_jsk_add ..... j1939_netdev_stop kref_put_lock(&priv->rx_kref, ...) kref_get(&priv->rx_kref, ...) REFCOUNT_WARN("addition on 0;...")

==================================================== refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 20874 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 RIP: 0010:refcount_warn_saturate+0x169/0x1e0 Call Trace: j1939_netdev_start+0x68b/0x920 j1939_sk_bind+0x426/0xeb0 ? security_socket_bind+0x83/0xb0

The rx_kref's kref_get() and kref_put() should use j1939_netdev_lock to protect.

Patch / fix

  • Linux Linux 5.4.156, 5.10.76, 5.14.15, 5.15
  • linux Debian 14, Debian 13, Debian 12 5.14.16-1

debian advisories DEBIAN-CVE-2021-47459

  • linux Ubuntu 20.04 LTS 5.4.0-92.103
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1061.64
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1059.63
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1010.11
  • linux-kvm Ubuntu 20.04 LTS 5.4.0-1051.53
  • linux-azure Ubuntu 20.04 LTS 5.4.0-1065.68
  • linux-gkeop Ubuntu 20.04 LTS 5.4.0-1029.30
  • linux-raspi Ubuntu 20.04 LTS 5.4.0-1048.53

ubuntu advisories UBUNTU-CVE-2021-47459

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

  • kernel RHEL 9 5.14.0-427.28.1.el9_4
  • rv RHEL 9 5.14.0-427.28.1.el9_4
  • perf RHEL 9 5.14.0-427.28.1.el9_4
  • rtla RHEL 9 5.14.0-427.28.1.el9_4
  • bpftool RHEL 9 7.3.0-427.28.1.el9_4
  • libperf RHEL 9 5.14.0-427.28.1.el9_4
  • kernel-rt RHEL 9 5.14.0-427.28.1.el9_4
  • kernel-64k RHEL 9 5.14.0-427.28.1.el9_4

red hat advisories RHSA-2024:4823RHSA-2024:4831RHSA-2024:4928

  • dtb-aarch64 openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-64kb SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-syms SLE Module for Development Tools 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-obs-qa openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-source SLE Module for Development Tools 15 SP5, SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-default SLE Workstation Extension 15 SP5, SLE Module for Legacy 15 SP5, SLE Module for Basesystem 15 SP5 +4 more 5.14.21-150500.55.68.1
  • kernel-kvmsmall openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.68.1

suse advisories SUSE-SU-2024:2190-1SUSE-SU-2024:2189-1SUSE-SU-2024:2019-1SUSE-SU-2024:2011-1SUSE-SU-2024:2008-1

  • kernel AlmaLinux 9 5.14.0-427.28.1.el9_4
  • rv AlmaLinux 9 5.14.0-427.28.1.el9_4
  • perf AlmaLinux 9 5.14.0-427.28.1.el9_4
  • rtla AlmaLinux 9 5.14.0-427.28.1.el9_4
  • bpftool AlmaLinux 9 7.3.0-427.28.1.el9_4
  • libperf AlmaLinux 9 5.14.0-427.28.1.el9_4
  • kernel-rt AlmaLinux 9 5.14.0-427.28.1.el9_4
  • kernel-64k AlmaLinux 9 5.14.0-427.28.1.el9_4

almalinux advisories ALSA-2024:4928

  • kernel Rocky Linux 9 5.14.0-427.28.1.el9_4.cloud.1.0
  • kernel Rocky Linux 9 5.14.0-427.28.1.el9_4

rocky linux advisories RXSA-2024:4928RLSA-2024:4928

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-2021-47459 updated cvss 7.8

kernel: can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: no fix available
  • Red Hat CodeReady Linux Builder EUS (v.9.2) kernel-debuginfo-common-s390x 5.14.0-284.75.1.el9_2, kernel-debuginfo-common-x86_64 5.14.0-284.75.1.el9_2, kernel-debuginfo-common-aarch64 5.14.0-284.75.1.el9_2, kernel-debuginfo-common-ppc64le 5.14.0-284.75.1.el9_2
    fixed: vendor fix RHSA-2024:4823
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-427.28.1.el9_4, perf 5.14.0-427.28.1.el9_4, rtla 5.14.0-427.28.1.el9_4, kernel-devel-matched 5.14.0-427.28.1.el9_4, kernel-64k-devel-matched 5.14.0-427.28.1.el9_4, kernel-debug-devel-matched 5.14.0-427.28.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:4928
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) perf 5.14.0-284.75.1.el9_2, rtla 5.14.0-284.75.1.el9_2, kernel-devel-matched 5.14.0-284.75.1.el9_2, kernel-64k-devel-matched 5.14.0-284.75.1.el9_2, kernel-debug-devel-matched 5.14.0-284.75.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.75.1.el9_2, +5 more
    fixed: vendor fix RHSA-2024:4823
  • Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.3.0-427.28.1.el9_4, kernel 5.14.0-427.28.1.el9_4, kernel-64k 5.14.0-427.28.1.el9_4, kernel-core 5.14.0-427.28.1.el9_4, kernel-tools 5.14.0-427.28.1.el9_4, python3-perf 5.14.0-427.28.1.el9_4, +28 more
    fixed: vendor fix RHSA-2024:4928
  • Red Hat Enterprise Linux BaseOS EUS (v.9.2) bpftool 7.0.0-284.75.1.el9_2, kernel 5.14.0-284.75.1.el9_2, kernel-64k 5.14.0-284.75.1.el9_2, kernel-core 5.14.0-284.75.1.el9_2, kernel-tools 5.14.0-284.75.1.el9_2, python3-perf 5.14.0-284.75.1.el9_2, +28 more
    fixed: vendor fix RHSA-2024:4823
  • Red Hat Enterprise Linux CRB (v. 9) libperf 5.14.0-427.28.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.28.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.28.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.28.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.28.1.el9_4 Red Hat Enterprise Linux NFV (v. 9) kernel-rt 5.14.0-427.28.1.el9_4, kernel-rt-kvm 5.14.0-427.28.1.el9_4, kernel-rt-core 5.14.0-427.28.1.el9_4, kernel-rt-modules 5.14.0-427.28.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.28.1.el9_4, kernel-rt-debug-core 5.14.0-427.28.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:4928
  • Red Hat Enterprise Linux Real Time EUS (v.9.2) kernel-rt 5.14.0-284.75.1.rt14.360.el9_2, kernel-rt-core 5.14.0-284.75.1.rt14.360.el9_2, kernel-rt-modules 5.14.0-284.75.1.rt14.360.el9_2, kernel-rt-debug-core 5.14.0-284.75.1.rt14.360.el9_2, kernel-rt-modules-core 5.14.0-284.75.1.rt14.360.el9_2, kernel-rt-debug-modules 5.14.0-284.75.1.rt14.360.el9_2, +4 more Red Hat Enterprise Linux Real Time for NFV EUS (v.9.2) kernel-rt 5.14.0-284.75.1.rt14.360.el9_2, kernel-rt-kvm 5.14.0-284.75.1.rt14.360.el9_2, kernel-rt-core 5.14.0-284.75.1.rt14.360.el9_2, kernel-rt-modules 5.14.0-284.75.1.rt14.360.el9_2, kernel-rt-debug-kvm 5.14.0-284.75.1.rt14.360.el9_2, kernel-rt-debug-core 5.14.0-284.75.1.rt14.360.el9_2, +6 more
    fixed: vendor fix RHSA-2024:4831
show 2 more
  • Red Hat Enterprise Linux RT (v. 9) kernel-rt 5.14.0-427.28.1.el9_4, kernel-rt-core 5.14.0-427.28.1.el9_4, kernel-rt-modules 5.14.0-427.28.1.el9_4, kernel-rt-debug-core 5.14.0-427.28.1.el9_4, kernel-rt-modules-core 5.14.0-427.28.1.el9_4, kernel-rt-debug-modules 5.14.0-427.28.1.el9_4, +4 more
    fixed: vendor fix RHSA-2024:4928
  • 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 Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux AppStream EUS (v.9.2) kernel-doc 5.14.0-284.75.1.el9_2
    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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.23% chance of exploitation in the next 30 days, higher than 13% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
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.