Linux Kernel up to 5.15.4 ALSA cs_desc null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 5.15.4. The affected element is the function cs_desc of the component ALSA. This manipulation causes null pointer dereference. The identification of this vulnerability is CVE-2021-47211. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 5.15.4. Affected by this vulnerability is the function cs_desc of the component ALSA. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. The summary by CVE is:

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.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2021-47211. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 237867 (Ubuntu 16.04 LTS / 18.04 LTS : Linux kernel vulnerabilities (USN-7553-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.15.5 or 5.16 eliminates this vulnerability. Applying the patch 58fa50de595f/b97053df0f04 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (237867). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.6
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 237867
Nessus Name: Ubuntu 16.04 LTS / 18.04 LTS : Linux kernel vulnerabilities (USN-7553-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Kernel 5.15.5/5.16
Patch: 58fa50de595f/b97053df0f04

Timelineinfo

04/10/2024 🔍
04/10/2024 +0 days 🔍
04/10/2024 +0 days 🔍
06/06/2025 +422 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2021-47211 (🔍)
GCVE (CVE): GCVE-0-2021-47211
GCVE (VulDB): GCVE-100-260299

Entryinfo

Created: 04/10/2024 21:35
Updated: 06/06/2025 16:07
Changes: 04/10/2024 21:35 (57), 05/16/2024 13:31 (1), 01/14/2025 17:15 (12), 06/06/2025 16:07 (2)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion

 305459538 (+0)
1 Year ago
How to fix this vulnerability in version 5.4 of the Linux kernel code
 VulDB Community Team1 Year ago
We don't assume that there is an official fix for 5.4.x. You would either have to upgrade to a supported release or apply the patches manually.

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