CVE Catalog

CVE-2026-120596

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Summary

A remotely exploitable denial-of-service vulnerability exists in the TCP options parser of the Nut/Net TCP/IP stack in Nut/OS (Ethernut/Egnite) up to version 5.1. An unauthenticated attacker can send a single TCP segment with an unknown option with a zero length byte, triggering an infinite loop in NutTcpInputOptions and blocking the TCP processing thread.

Risk Assessment

All TCP-based services on the device become unresponsive until reboot, potentially paralyzing device operation.

Recommendation

Upgrade Nut/OS to a fixed version or implement measures to restrict access to TCP ports.

Related vulnerabilities

Original NVD description (English source)

A remotely exploitable denial-of-service vulnerability exists in the TCP options parser of the Nut/Net TCP/IP stack included in Nut/OS, developed by Ethernut/Egnite. Nut/OS releases up to version 5.1 are affected. An unauthenticated attacker can send a single TCP segment containing an unknown TCP option with a length byte of zero to any open TCP port on a vulnerable device. When processed, this malformed option triggers an infinite loop in the function NutTcpInputOptions, permanently blocking the TCP processing thread and rendering all TCP-based services unresponsive until the device is rebooted.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS