CVE-2021-47053: 
Linux Debian vulnerability analysis and mitigation

CVE-2021-47053 affects the Linux kernel's crypto subsystem, specifically in the sun8i-ss hash algorithm implementation. The vulnerability was discovered and resolved in 2021, involving a memory leak in the pad allocation within the crypto: sun8i-ss driver. The issue occurs when several failure return paths don't properly free the allocated pad memory (Kernel Git).

The vulnerability exists in the sun8i-ss hash algorithm implementation where memory allocated for 'pad' is not properly freed in certain error paths. The issue was introduced in commit d9b45418a917 ("crypto: sun8i-ss - support hash algorithms") and was later fixed by ensuring proper memory cleanup in all execution paths. The fix involves adding proper memory cleanup in error handling paths and reorganizing the cleanup code to prevent memory leaks (Kernel Git).

The vulnerability results in memory leaks in the Linux kernel's crypto subsystem. When triggered, it can lead to gradual system memory depletion, potentially affecting system stability and performance over time (CVE Mitre).

The vulnerability requires local access to the system and the ability to interact with the crypto subsystem. It is primarily triggered through the failure paths in the hash algorithm implementation, making it a reliability issue rather than a security exploit vector (Debian Security).

The issue has been fixed in the Linux kernel through a patch that properly handles memory cleanup in all execution paths. The fix has been backported to various stable kernel versions. Users should update their Linux kernel to a version that includes the fix. For Debian systems, fixed versions are available in bullseye (5.10.226-1), bookworm (6.1.128-1), and later releases (Debian Security).