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🛡️ CVE-2026-41429 — arduino-esp32

🟠 CVSS 8.8 — High ⚠️ Exploit Public CWE-121 NVD
8.8
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached from an adjacent network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Adjacent network — the attacker has to sit on the same local or logical network.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2026-41429 is classified as CWE-121: Stack-based Buffer Overflow. An oversized write to a stack buffer overwrites saved state such as return addresses, which can redirect execution.

Affected software

CVE-2026-41429 is recorded against 1 package.

  • arduino-esp32 (fixed in 3.3.8)

Timeline and source

Published on 24 April 2026 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. Record sourced from NVD.

References

github.com
github.com

Other advisories for this package

arduino-esp32 has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-121: Stack-based Buffer Overflow) in other software:

Details

Severity HIGH
CVSS Score 8.8
CVSS Vector CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE CWE-121
Public Exploit ⚠️ Yes
Source NVD
Published 2026-04-24
Updated 2026-08-20
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
arduino-esp32 — 3.3.8

Similar Threats

Exploit Protection

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CVE-2026-41429 carries CVSS 8.8 High rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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