Vulnerability-Lookup

GHSA-MG75-66WV-HFXW

Vulnerability from github – Published: 2026-11-02 18:32 – Updated: 2026-11-02 18:32

Details

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.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-120596"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-835"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-11-02T17:17:40Z",
    "severity": "HIGH"
  },
  "details": "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": "GHSA-mg75-66wv-hfxw",
  "modified": "2026-11-02T18:32:28Z",
  "published": "2026-11-02T18:32:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-120596"
    },
    {
      "type": "WEB",
      "url": "https://www.ethernut.de/en/download/index.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-120596 (GCVE-0-2026-120596)

Vulnerability from cvelistv5 – Published: 2026-11-02 17:04 – Updated: 2026-11-02 17:17

Title

CVE-2026-120596

Summary

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-11-02 17:17 UTC

CWE

CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-20 Improper Input Validation
CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')

Assigner

certcc CNA under the mitre root

CNA scorecard E 42/100 over 172 records in the last 180 days details

References

1 reference

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

Impacted products

1 product

Vendor	Product	Version
Ethernut / egnite GmbH	Nut/Net TCP/IP Stack	Affected: Nut/OS 5.1

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "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"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-120596",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-11-02T17:17:32.319063Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-835",
                "description": "CWE-835 Loop with Unreachable Exit Condition (\u0027Infinite Loop\u0027)",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-11-02T17:17:35.066Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Nut/Net TCP/IP Stack",
          "vendor": "Ethernut / egnite GmbH",
          "versions": [
            {
              "status": "affected",
              "version": "Nut/OS 5.1"
            }
          ]
        }
      ],
      "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": [
            {
              "description": "CWE-835 Loop with Unreachable Exit Condition (\u0027Infinite Loop\u0027)",
              "lang": "en"
            }
          ]
        },
        {
          "descriptions": [
            {
              "description": "CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer",
              "lang": "en"
            }
          ]
        },
        {
          "descriptions": [
            {
              "description": "CWE-20 Improper Input Validation",
              "lang": "en"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-02T17:04:18.611Z",
        "orgId": "37e5125f-f79b-445b-8fad-9564f167944b",
        "shortName": "certcc"
      },
      "references": [
        {
          "url": "https://www.ethernut.de/en/download/index.html"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "CVE-2026-120596",
      "x_generator": {
        "engine": "VINCE 3.0.52",
        "env": "prod",
        "origin": "https://cveawg.mitre.org/api/cve/CVE-2026-120596"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "37e5125f-f79b-445b-8fad-9564f167944b",
    "assignerShortName": "certcc",
    "cveId": "CVE-2026-120596",
    "datePublished": "2026-11-02T17:04:18.611Z",
    "dateReserved": "2026-11-02T16:58:49.331Z",
    "dateUpdated": "2026-11-02T17:17:35.066Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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