CVE-2021-28952: 
Linux Kernel vulnerability analysis and mitigation

CVE-2021-28952 is a buffer overflow vulnerability discovered in the Linux kernel through version 5.11.8. The vulnerability specifically affects the sound/soc/qcom/sdm845.c soundwire device driver when an unexpected port ID number is encountered. The issue was fixed in Linux kernel version 5.12-rc4 (NVD).

The vulnerability stems from an array out-of-bounds write issue in the soundwire device driver where the MAX AFE port ID was incorrectly set to 16 instead of using the AFE_PORT_MAX macro. This implementation error could lead to buffer overflow conditions when handling unexpected port ID numbers. The vulnerability has been assigned a CVSS v3.1 base score of 7.8 (HIGH) with the vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (NVD, NetApp Advisory).

Successful exploitation of this vulnerability could lead to multiple severe consequences including disclosure of sensitive information, addition or modification of data, or denial of service (DoS). The high CVSS score indicates that the vulnerability could potentially allow an attacker to execute arbitrary code with elevated privileges (NetApp Advisory).

The vulnerability requires local access and low privileges to exploit. While public discussion of this vulnerability exists, no specific details about active exploitation in the wild have been publicly reported (NetApp Advisory).

The vulnerability has been fixed in Linux kernel version 5.12-rc4. The fix involves properly using the AFE_PORT_MAX macro instead of the hardcoded value for maximum AFE port ID. Various Linux distributions have released patches to address this vulnerability, including Fedora 32, 33, and 34 through their respective kernel updates (Kernel Patch, Fedora Update).