CVE-2021-47116: 
Linux Kernel vulnerability analysis and mitigation

CVE-2021-47116 is a memory leak vulnerability in the Linux kernel's ext4 filesystem component, specifically in the ext4_mb_init_backend function. The vulnerability was discovered by syzbot and occurs when a filesystem is corrupted with an illegally large s_log_groups_per_flex value (Red Hat Portal).

The vulnerability is a memory leak in the ext4_mb_init_backend function's error path. It occurs when handling filesystems with an illegally large s_log_groups_per_flex value (greater than or equal to 32). The issue has been assigned a CVSS v3.1 base score of 4.7 by Red Hat, with an attack vector of Local, high attack complexity, and low privileges required. The vulnerability primarily affects system availability (Red Hat Portal, Kernel Commit).

The vulnerability's primary impact is on system availability through memory leakage. It has been rated with High availability impact, while having no direct impact on confidentiality or integrity of the system (Red Hat Portal).

The vulnerability requires local access and low privileges to exploit. The attack complexity is rated as high by Red Hat, indicating that specific conditions need to be met for successful exploitation (Red Hat Portal).

The vulnerability has been fixed in the Linux kernel through a patch that corrects the error path in ext4_mb_init_backend by changing the error handling from 'err_freesgi' to 'err_freebuddy' (Kernel Commit).