Vulnerability · Published Apr 24, 2026 · Assigned by GitHub_M
CVE-2026-41429Improper validation of NBNS name_len in arduino-esp32 NetBIOS leads to memory corruption
High 8.8
In plain English
A high-severity stack buffer overflow in arduino-esp32 from espressif. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities).
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| espressif | arduino-esp32 | < 3.3.8 |
Weakness: CWE-121 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H