CVE-2023-53380: 
Linux Kernel vulnerability analysis and mitigation

A vulnerability in the Linux kernel's RAID10 implementation has been identified as CVE-2023-53380. The issue involves a null pointer dereference of 'mreplace' in raid10syncrequest function. The vulnerability was disclosed on September 18, 2025, affecting various Linux kernel versions (NVD).

The vulnerability stems from inconsistent checks of 'mreplace' in raid10syncrequest(). There are two separate checks: the first check sets 'needreplace' and uses 'mreplace' later if no-Faulty 'mreplace' exists, while in the second check, 'mreplace' is set to NULL if it is Faulty, but 'needreplace' remains unchanged. This can lead to a null pointer dereference if Faulty is set between the two checks (Ubuntu).

The vulnerability affects multiple Linux distributions and their kernel variants, including Ubuntu's various kernel packages such as linux-hwe, linux-aws, linux-azure, and others. Several Ubuntu releases from 18.04 LTS to 24.04 LTS are affected, with some packages requiring updates (Ubuntu).

The issue has been fixed by merging the two checks into one and replacing 'need_replace' with 'mreplace' since their values are always the same. Various Linux distributions have released patches for affected kernel versions. Ubuntu has provided fixes for multiple kernel packages across different releases (Ubuntu).