CVE-2020-10070: 
NixOS vulnerability analysis and mitigation

CVE-2020-10070 affects the MQTT code in the Zephyr Project, where improper bounds checking can result in memory corruption and potentially remote code execution. The vulnerability was identified as NCC-ZEP-031 and affects Zephyr version 2.2.0 and later versions (NVD).

The vulnerability stems from improper bounds checking in the MQTT buffer on receive operations. When calculating the packet length, arithmetic overflow can result in accepting a receive buffer larger than the available buffer space, leading to user data being written beyond the intended buffer boundaries. The issue has been assigned a CVSS v3.1 base score of 9.8 (CRITICAL) with vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (NVD).

The vulnerability can lead to memory corruption and potentially allow remote code execution on affected systems. This poses a significant risk as it could allow attackers to gain unauthorized control over affected devices running the Zephyr MQTT implementation (NVD).

The vulnerability can be exploited remotely without requiring any authentication or user interaction. The attack complexity is rated as low, making it relatively straightforward to exploit (NVD).

The vulnerability has been fixed in Zephyr version 2.3.0 through commit 0b39cbf3, which improves buffer bounds validation in mqtt_read_message_chunk. The fix includes more strict verification of data read from transport to ensure it fits into the RX buffer and switches to unsigned integers where possible to prevent unnecessary signed/unsigned operations (GitHub Patch).