CVE-2026-41429Public exploit

Device crash via unchecked NBNS name length

Published Apr 24, 2026 · Updated Apr 24, 2026

Stack-based buffer overflow in Arduino-ESP32 before 3.3.8 allows remote attackers to crash or reset devices via crafted NBNS requests. In NetBIOS::_onPacket(), an unchecked name_len reaches _getnbname() and then controls memcpy() into the fixed 33-byte nbnsa.name stack buffer. Reachability requires firmware to call NBNS.begin(...), which exposes UDP port 137 on the local network; the demonstrated consequence is memory corruption causing a crash or reset.

CVSS severity8.8
High
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in Arduino-ESP32 before 3.3.8 allows remote attackers to crash or reset devices via crafted NBNS requests. In NetBIOS::_onPacket(), an unchecked name_len reaches _getnbname() and then controls memcpy() into the fixed 33-byte nbnsa.name stack buffer. Reachability requires firmware to call NBNS.begin(...), which exposes UDP port 137 on the local network; the demonstrated consequence is memory corruption causing a crash or reset.

The record

CVE
CVE-2026-41429
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
Espressif Systems
Product
Arduino-ESP32
Classifications
CWE-121, T1190
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.3.8

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Espressif Systems · Arduino-ESP32version=< 3.3.8

Published CVSS scores

8.8GitHub, Inc.CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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