CVE-2026-84698: Out-of-bounds Write in PX4 PX4-Autopilot

CVE-2026-84698 is a heap buffer overflow vulnerability in PX4-Autopilot's sd_bench command. The vulnerability arises because the command writes a fixed four-byte block number into a buffer allocated based on user input, which can be smaller than four bytes. This mismatch allows an attacker to overflow the heap buffer, potentially leading to code execution or system instability. The vulnerability affects PX4-Autopilot versions up to and including 1.17.0. The CVSS 4.0 base score is 7.1, indicating a high severity with network attack vector, low attack complexity, no privileges or user interaction required, and high impact on availability.

Successful exploitation can cause a heap buffer overflow that may result in a system crash or arbitrary code execution, impacting the availability and potentially the integrity of the PX4-Autopilot system. The vulnerability does not require privileges or user interaction and can be triggered remotely over the network.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, users should avoid invoking the sd_bench command with block sizes below four bytes or restrict access to this functionality to trusted users only.