CVE-2020-10021: 
NixOS vulnerability analysis and mitigation

CVE-2020-10021 is a vulnerability discovered in the Zephyr Real-Time Operating System (RTOS) that involves an Out-of-bounds Write in the USB Mass Storage memoryWrite handler with unaligned Sizes. The vulnerability affects zephyrproject-rtos zephyr version 1.14.1 and later versions, as well as version 2.1.0 and later versions (CVE-MITRE).

The vulnerability is classified as an Out-of-bounds Write (CWE-787) that occurs in the USB Mass Storage memoryWrite handler when dealing with unaligned sizes. The issue manifests when the page buffer can overflow if dCBWDataTransferLength is multiple of the BLOCK_SIZE but the host uses OUT packets smaller than MPS during transfer (GitHub-PR-23240).

The vulnerability could potentially lead to memory corruption when processing USB Mass Storage write operations, which could result in system crashes or potential code execution within the affected scope (CVE-MITRE).

The vulnerability requires physical access to the device through USB connection to be exploited. An attacker could trigger the vulnerability by sending specifically crafted USB Mass Storage write commands with unaligned sizes (GitHub-PR-23240).

The issue has been fixed in releases v1.14.2 and v2.2.0. The fix includes implementing proper checks for LBA range and addressing the page buffer overflow condition. Users are recommended to upgrade to these patched versions (GitHub-PR-23455, GitHub-PR-23456).