{"id":"CVE-2026-120596","title":"CVE-2026-120596","summary":"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 atta…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"adp","cwe":["CWE-835","CWE-119","CWE-20"],"vendor":"Ethernut / egnite GmbH","product":"Nut/Net TCP/IP Stack","affected":["nut_net_tcp_ip_stack Nut/OS 5.1"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-11-02T17:17:32.319063Z"},"published":"2026-11-02","updated":"2026-11-02","sourceUpdated":"2026-11-02T17:17:35.066Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-120596","references":[{"url":"https://www.ethernut.de/en/download/index.html"}],"tags":["cve.org"],"epss":0.00375,"epssPercentile":0.31726,"ingestedAt":"2026-11-05T19:30:42.724Z","slug":"CVE-2026-120596","body":"## Overview\n\nA 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.\n\n## Affected\n\n- `nut_net_tcp_ip_stack Nut/OS 5.1`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}