CVE-2026-41429 HIGH

CVE-2026-41429: Improper validation of NBNS name_len in arduino-esp32 NetBIOS leads to memory corruption

Vendor Espressif
Product arduino-esp32
Weakness CWE-121
Published April 24, 2026
Last update April 27, 2026

CVSS base score

8.8/10
Attack vector Adjacent
Attack complexity Low
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

What the vulnerability does

01Description

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, there is a remotely reachable memory corruption issue in the NBNS packet handling path. When NetBIOS is enabled by calling NBNS.begin(...), the device listens on UDP port 137 and processes untrusted NBNS requests from the local network. The request parser trusts the attacker-controlled name_len field without enforcing a bound consistent with the fixed-size destination buffers used later in the flow. This vulnerability is fixed in 3.3.8.

Key dates

02Disclosure timeline

April 24, 2026 CVE published
April 27, 2026 Record updated