Skip to content
Fencer Vulns
medium 5.5

CVE-2021-47211 json

ALSA: usb-audio: fix null pointer dereference on pointer cs_desc

published 2024-04-10 2 y ago modified 2026-06-19 4 mo ago also EUVD-2021-33859

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

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

ALSA: usb-audio: fix null pointer dereference on pointer cs_desc

The pointer cs_desc return from snd_usb_find_clock_source could be null, so there is a potential null pointer dereference issue. Fix this by adding a null check before dereference.

Patch / fix

  • Linux Linux 5.10.259, 5.15.5, 5.16
  • linux Debian 14, Debian 13, Debian 12 5.15.5-1

debian advisories DEBIAN-CVE-2021-47211

  • linux Ubuntu Pro 16.04 LTS 4.4.0-269.303
  • linux Ubuntu Pro 18.04 LTS 4.15.0-238.250
  • linux Ubuntu Pro 20.04 LTS 5.4.0-218.238
  • linux-aws Ubuntu Pro 14.04 LTS 4.4.0-1144.150
  • linux-aws Ubuntu Pro 16.04 LTS 4.4.0-1182.197
  • linux-aws Ubuntu Pro 18.04 LTS 4.15.0-1181.194
  • linux-aws Ubuntu Pro 20.04 LTS 5.4.0-1147.157
  • linux-gcp Ubuntu Pro 16.04 LTS 4.15.0-1174.191~16.04.1

ubuntu advisories UBUNTU-CVE-2021-47211

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-syms SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.216.1
  • kernel-source SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.216.1
  • kernel-default SLES for SAP 12 SP5, SLES 12 SP5, SLE Workstation Extension 12 SP5 +2 more 4.12.14-122.216.1
  • kernel-obs-build SLE Software Development Kit 12 SP5 4.12.14-122.216.1
  • kernel-rt SLE Micro 5.5, Real Time Module 15 SP5, openSUSE Leap 15.5 5.14.21-150500.13.52.1
  • kernel-syms-rt Real Time Module 15 SP5, openSUSE Leap 15.5 5.14.21-150500.13.52.1
  • kernel-rt_debug Real Time Module 15 SP5, openSUSE Leap 15.5 5.14.21-150500.13.52.1
  • kernel-source-rt SLE Micro 5.5, Real Time Module 15 SP5, openSUSE Leap 15.5 5.14.21-150500.13.52.1

suse advisories SUSE-SU-2024:1870-1SUSE-SU-2024:1663-1SUSE-SU-2024:1659-1SUSE-SU-2024:1647-1SUSE-SU-2024:1646-1SUSE-SU-2024:1644-1

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-2021-47211 updated cvss 4.4

kernel: ALSA: usb-audio: fix null pointer dereference on pointer cs_desc

  • 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: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    affected: no fix available
  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 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

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
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.