Denial-of-Service Vulnerability in Nut/OS by Ethernut/Egnite
CVE-2026-120596

7.5HIGH

Key Information:

Vendor

Ethernut / Egnite Gmbh

Status
Nut/net Tcp/ip Stack
Vendor
CVE Published:
2 November 2026

What is CVE-2026-120596?

A denial-of-service vulnerability exists in the TCP options parser of the Nut/Net TCP/IP stack included in Nut/OS, affecting releases up to version 5.1. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted TCP segment containing an invalid TCP option. This manipulated segment triggers an infinite loop within the NutTcpInputOptions function, causing the TCP processing thread to become unresponsive. As a result, all TCP-based services on the device are rendered inactive, necessitating a device reboot to restore functionality.

Affected Version(s)

Nut/Net TCP/IP Stack Nut/OS 5.1

References

https://www.ethernut.de/en/download/index.html

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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