CVE-2026-120596

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-120596", "assignerOrgId": "37e5125f-f79b-445b-8fad-9564f167944b", "state": "PUBLISHED", "assignerShortName": "certcc", "dateReserved": "2026-11-02T16:58:49.331Z", "datePublished": "2026-11-02T17:04:18.611Z", "dateUpdated": "2026-11-02T17:17:35.066Z"}, "containers": {"cna": {"title": "CVE-2026-120596", "descriptions": [{"lang": "en", "value": "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."}], "source": {"discovery": "UNKNOWN"}, "affected": [{"vendor": "Ethernut / egnite GmbH", "product": "Nut/Net TCP/IP Stack", "versions": [{"status": "affected", "version": "Nut/OS 5.1"}]}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')"}]}, {"descriptions": [{"lang": "en", "description": "CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer"}]}, {"descriptions": [{"lang": "en", "description": "CWE-20 Improper Input Validation"}]}], "references": [{"url": "https://www.ethernut.de/en/download/index.html"}], "x_generator": {"engine": "VINCE 3.0.52", "env": "prod", "origin": "https://cveawg.mitre.org/api/cve/CVE-2026-120596"}, "providerMetadata": {"orgId": "37e5125f-f79b-445b-8fad-9564f167944b", "shortName": "certcc", "dateUpdated": "2026-11-02T17:04:18.611Z"}}, "adp": [{"problemTypes": [{"descriptions": [{"type": "CWE", "cweId": "CWE-835", "lang": "en", "description": "CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')"}]}], "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}}, {"other": {"type": "ssvc", "content": {"timestamp": "2026-11-02T17:17:32.319063Z", "id": "CVE-2026-120596", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-11-02T17:17:35.066Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}}, {"other": {"type": "ssvc", "content": {"id": "CVE-2026-120596", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-11-02T17:17:32.319063Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-835", "description": "CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')"}]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-11-02T17:17:28.470Z"}}], "cna": {"title": "CVE-2026-120596", "source": {"discovery": "UNKNOWN"}, "affected": [{"vendor": "Ethernut / egnite GmbH", "product": "Nut/Net TCP/IP Stack", "versions": [{"status": "affected", "version": "Nut/OS 5.1"}]}], "references": [{"url": "https://www.ethernut.de/en/download/index.html"}], "x_generator": {"env": "prod", "engine": "VINCE 3.0.52", "origin": "https://cveawg.mitre.org/api/cve/CVE-2026-120596"}, "descriptions": [{"lang": "en", "value": "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."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')"}]}, {"descriptions": [{"lang": "en", "description": "CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer"}]}, {"descriptions": [{"lang": "en", "description": "CWE-20 Improper Input Validation"}]}], "providerMetadata": {"orgId": "37e5125f-f79b-445b-8fad-9564f167944b", "shortName": "certcc", "dateUpdated": "2026-11-02T17:04:18.611Z"}}}, "cveMetadata": {"cveId": "CVE-2026-120596", "state": "PUBLISHED", "dateUpdated": "2026-11-02T17:17:35.066Z", "dateReserved": "2026-11-02T16:58:49.331Z", "assignerOrgId": "37e5125f-f79b-445b-8fad-9564f167944b", "datePublished": "2026-11-02T17:04:18.611Z", "assignerShortName": "certcc"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"product": "Nut/Net TCP/IP Stack", "vendor": "Ethernut / egnite GmbH", "versions": [{"status": "affected", "version": "Nut/OS 5.1"}]}], "source": "cret@cert.org"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2026-120596", "lastModified": "2026-11-02T19:35:33.347", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-120596", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-11-02T17:17:32.319063Z", "version": "2.0.3"}}]}, "published": "2026-11-02T17:17:40.003", "references": [{"source": "cret@cert.org", "url": "https://www.ethernut.de/en/download/index.html"}], "sourceIdentifier": "cret@cert.org", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-835"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "Nut/OS 5.1"}}], "enrichment": {"confidence": 100.0, "confidence_source": "manual", "scores": [{"score": 100.0, "source": "manual"}]}, "original": {"product": "Nut/Net TCP/IP Stack", "source": "cna", "vendor": "Ethernut / egnite GmbH"}, "product": "nut/os", "vendor": "ethernut"}], "created": "2026-11-02T18:45:13.292139+00:00", "title": "Denial-of-Service via Malformed TCP Options in Nut/Net TCP/IP Stack", "updated": "2026-11-03T16:25:46.402452+00:00", "vendors": ["ethernut", "ethernut$PRODUCT$nut/os"]}