CVE-2026-42854 arduino-esp32: Stack buffer overflow in WebServer multipart boundary parsing leads to remote crash potential RCE

arduino-esp32 is an Arduino core for the ESP32, ESP32-S2, ESP32-S3, ESP32-C3, ESP32-C6 and ESP32-H2 microcontrollers. Prior to 3.3.8, the WebServer multipart form parser in arduino-esp32 allocates a Variable Length Array VLA on the stack whose size is derived from an attacker-controlled HTTP head...