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Fencer Vulns
high 7.5

CVE-2021-47559 json

net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk()

published 2024-05-24 2 y ago modified 2026-08-05 3 mo ago also EUVD-2021-34561

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

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

net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk()

Coverity reports a possible NULL dereferencing problem:

in smc_vlan_by_tcpsk(): 6. returned_null: netdev_lower_get_next returns NULL (checked 29 out of 30 times). 7. var_assigned: Assigning: ndev = NULL return value from netdev_lower_get_next. 1623 ndev = (struct net_device *)netdev_lower_get_next(ndev, &lower); CID 1468509 (#1 of 1): Dereference null return value (NULL_RETURNS) 8. dereference: Dereferencing a pointer that might be NULL ndev when calling is_vlan_dev. 1624 if (is_vlan_dev(ndev)) {

Remove the manual implementation and use netdev_walk_all_lower_dev() to iterate over the lower devices. While on it remove an obsolete function parameter comment.

Patch / fix

  • Linux Linux 5.10.83, 5.15.6, 5.16
  • linux Debian 14, Debian 13, Debian 12 5.15.15-1

debian advisories DEBIAN-CVE-2021-47559

  • kernel RHEL 9.0 E4S 5.14.0-70.117.1.el9_0
  • perf RHEL 9.0 E4S 5.14.0-70.117.1.el9_0
  • bpftool RHEL 9.0 E4S 5.14.0-70.117.1.el9_0
  • kernel-core RHEL 9.0 E4S 5.14.0-70.117.1.el9_0
  • kernel-tools RHEL 9.0 E4S 5.14.0-70.117.1.el9_0
  • python3-perf RHEL 9.0 E4S 5.14.0-70.117.1.el9_0
  • kernel-modules RHEL 9.0 E4S 5.14.0-70.117.1.el9_0
  • kernel-zfcpdump RHEL 9.0 E4S 5.14.0-70.117.1.el9_0

red hat advisories RHSA-2024:6991RHSA-2024:6990

  • kernel-syms SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.225.1
  • kernel-source SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.225.1
  • kernel-default SLES for SAP 12 SP5, SLES 12 SP5, SLE Workstation Extension 12 SP5 +2 more 4.12.14-122.225.1
  • kernel-obs-build SLE Software Development Kit 12 SP5 4.12.14-122.225.1
  • kernel-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.194.1
  • kernel-syms-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.194.1
  • kernel-source-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.194.1
  • kernel-rt SLE Real Time 12 SP5 4.12.14-10.197.1

suse advisories SUSE-SU-2024:2940-1SUSE-SU-2024:2901-1SUSE-SU-2024:2892-1SUSE-SU-2024:2190-1SUSE-SU-2024:2189-1SUSE-SU-2024:2019-1

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-2021-47559 updated cvss 5.5

kernel: net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk()

  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) perf 5.14.0-70.117.1.el9_0, kernel-devel-matched 5.14.0-70.117.1.el9_0, kernel-debug-devel-matched 5.14.0-70.117.1.el9_0, kernel-debuginfo-common-s390x 5.14.0-70.117.1.el9_0, kernel-zfcpdump-devel-matched 5.14.0-70.117.1.el9_0, kernel-debuginfo-common-x86_64 5.14.0-70.117.1.el9_0, +2 more Red Hat Enterprise Linux BaseOS E4S (v.9.0) kernel 5.14.0-70.117.1.el9_0, bpftool 5.14.0-70.117.1.el9_0, kernel-core 5.14.0-70.117.1.el9_0, kernel-tools 5.14.0-70.117.1.el9_0, python3-perf 5.14.0-70.117.1.el9_0, kernel-modules 5.14.0-70.117.1.el9_0, +14 more
    fixed: vendor fix RHSA-2024:6991
  • Red Hat Enterprise Linux NFV E4S (v.9.0) kernel-rt 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-kvm 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-core 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-modules 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-debug-kvm 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-debug-core 5.14.0-70.117.1.rt21.189.el9_0, +4 more Red Hat Enterprise Linux Real Time E4S (v.9.0) kernel-rt 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-core 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-modules 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-debug-core 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-debug-modules 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-modules-extra 5.14.0-70.117.1.rt21.189.el9_0, +2 more
    fixed: vendor fix RHSA-2024:6990
  • 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
    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

0.47% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.