Vulnerability-Lookup

CVE-2026-87121 (GCVE-0-2026-87121)

Vulnerability from cvelistv5 – Published: 2026-09-22 19:48 – Updated: 2026-09-22 20:23

Title

Out-of-bounds write in lwIP TCP/IP Stack MQTT Client Application

Summary

lwIP TCP/IP Stack MQTT is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device.

Severity

9.8 (Critical)


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

9.3 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-22 20:23 UTC

CWE

CWE-787

Assigner

icscert CNA under the icscert root

CNA scorecard B 75/100 over 343 records in the last 180 days details

References

3 references

URL	Tags
https://savannah.nongnu.org/projects/lwip
https://www.cisa.gov/news-events/ics-advisories/i…
https://github.com/cisagov/CSAF/blob/develop/csaf…

Impacted products

1 product

Vendor	Product	Version	CPE status
lwIP	TCP/IP Stack MQTT	Affected: 2.0.1 , ≤ 2.2.1 (custom)	guessed

Date Public

2026-09-22 17:53

Credits

Shahriyar Jalayeri of ByteRay Ltd. reported this vulnerability to CISA.

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-87121",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-22T20:23:00.531481Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-22T20:23:09.069Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "TCP/IP Stack MQTT",
          "vendor": "lwIP",
          "versions": [
            {
              "lessThanOrEqual": "2.2.1",
              "status": "affected",
              "version": "2.0.1",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Shahriyar Jalayeri of ByteRay Ltd. reported this vulnerability to CISA."
        }
      ],
      "datePublic": "2026-09-22T17:53:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "lwIP\u0026nbsp;TCP/IP Stack MQTT\u0026nbsp;is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device."
            }
          ],
          "value": "lwIP\u00a0TCP/IP Stack MQTT\u00a0is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        },
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 9.3,
            "baseSeverity": "CRITICAL",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-787",
              "description": "CWE-787",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-22T19:51:50.077Z",
        "orgId": "7d14cffa-0d7d-4270-9dc0-52cabd5a23a6",
        "shortName": "icscert"
      },
      "references": [
        {
          "url": "https://savannah.nongnu.org/projects/lwip"
        },
        {
          "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-01"
        },
        {
          "url": "https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-265-01.json"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Users of lwIP are encouraged to update their version of lwIP using the repository found at\u0026nbsp;\u003ca href=\"https://savannah.nongnu.org/projects/lwip\"\u003ehttps://savannah.nongnu.org/projects/lwip\u003c/a\u003e. The commit identifier that contains the fix is f89407ea711879c04d91c92b35d67be78bbaf0f1."
            }
          ],
          "value": "Users of lwIP are encouraged to update their version of lwIP using the repository found at\u00a0 https://savannah.nongnu.org/projects/lwip . The commit identifier that contains the fix is f89407ea711879c04d91c92b35d67be78bbaf0f1."
        }
      ],
      "source": {
        "advisory": "ICSA-26-265-01",
        "discovery": "EXTERNAL"
      },
      "title": "Out-of-bounds write in lwIP TCP/IP Stack MQTT Client Application",
      "x_generator": {
        "engine": "Vulnogram 1.0.5"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "7d14cffa-0d7d-4270-9dc0-52cabd5a23a6",
    "assignerShortName": "icscert",
    "cveId": "CVE-2026-87121",
    "datePublished": "2026-09-22T19:48:25.046Z",
    "dateReserved": "2026-09-09T21:28:27.099Z",
    "dateUpdated": "2026-09-22T20:23:09.069Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-87121",
      "date": "2026-11-12",
      "epss": "0.00775",
      "percentile": "0.56264"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "TCP/IP Stack MQTT",
                "vendor": "lwIP",
                "versions": [
                  {
                    "lessThanOrEqual": "2.2.1",
                    "status": "affected",
                    "version": "2.0.1",
                    "versionType": "custom"
                  }
                ]
              }
            ],
            "source": "ics-cert@hq.dhs.gov"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "lwIP\u00a0TCP/IP Stack MQTT\u00a0is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device."
          }
        ],
        "id": "CVE-2026-87121",
        "lastModified": "2026-09-23T19:42:48.540",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 5.9,
              "source": "ics-cert@hq.dhs.gov",
              "type": "Secondary"
            }
          ],
          "cvssMetricV40": [
            {
              "cvssData": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "NONE",
                "attackVector": "NETWORK",
                "availabilityRequirement": "NOT_DEFINED",
                "baseScore": 9.3,
                "baseSeverity": "CRITICAL",
                "confidentialityRequirement": "NOT_DEFINED",
                "exploitMaturity": "NOT_DEFINED",
                "integrityRequirement": "NOT_DEFINED",
                "modifiedAttackComplexity": "NOT_DEFINED",
                "modifiedAttackRequirements": "NOT_DEFINED",
                "modifiedAttackVector": "NOT_DEFINED",
                "modifiedPrivilegesRequired": "NOT_DEFINED",
                "modifiedSubAvailabilityImpact": "NOT_DEFINED",
                "modifiedSubConfidentialityImpact": "NOT_DEFINED",
                "modifiedSubIntegrityImpact": "NOT_DEFINED",
                "modifiedUserInteraction": "NOT_DEFINED",
                "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
                "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
                "modifiedVulnIntegrityImpact": "NOT_DEFINED",
                "privilegesRequired": "NONE",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "NONE",
                "subIntegrityImpact": "NONE",
                "userInteraction": "NONE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
                "version": "4.0",
                "vulnAvailabilityImpact": "HIGH",
                "vulnConfidentialityImpact": "HIGH",
                "vulnIntegrityImpact": "HIGH",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "source": "ics-cert@hq.dhs.gov",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-87121",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "yes"
                  },
                  {
                    "technicalImpact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-22T20:23:00.531481Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-09-22T20:17:09.967",
        "references": [
          {
            "source": "ics-cert@hq.dhs.gov",
            "url": "https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-265-01.json"
          },
          {
            "source": "ics-cert@hq.dhs.gov",
            "url": "https://savannah.nongnu.org/projects/lwip"
          },
          {
            "source": "ics-cert@hq.dhs.gov",
            "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-01"
          }
        ],
        "sourceIdentifier": "ics-cert@hq.dhs.gov",
        "vulnStatus": "Awaiting Analysis",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-787"
              }
            ],
            "source": "ics-cert@hq.dhs.gov",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "current_release_date": "2026-10-09T06:16:42+00:00",
      "cve": "CVE-2026-87121",
      "id": "CVE-2026-87121",
      "initial_release_date": "2026-09-22T19:48:25.046000+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "lwip: lwip: Arbitrary code execution via MQTT out-of-bounds write",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-87121.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-87121",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-09-22T20:23:00.531481Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-09-22T20:23:05.983Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "TCP/IP Stack MQTT",
              "vendor": "lwIP",
              "versions": [
                {
                  "lessThanOrEqual": "2.2.1",
                  "status": "affected",
                  "version": "2.0.1",
                  "versionType": "custom"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "finder",
              "value": "Shahriyar Jalayeri of ByteRay Ltd. reported this vulnerability to CISA."
            }
          ],
          "datePublic": "2026-09-22T17:53:00.000Z",
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "lwIP\u0026nbsp;TCP/IP Stack MQTT\u0026nbsp;is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device."
                }
              ],
              "value": "lwIP\u00a0TCP/IP Stack MQTT\u00a0is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            },
            {
              "cvssV4_0": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "NONE",
                "attackVector": "NETWORK",
                "baseScore": 9.3,
                "baseSeverity": "CRITICAL",
                "exploitMaturity": "NOT_DEFINED",
                "privilegesRequired": "NONE",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "NONE",
                "subIntegrityImpact": "NONE",
                "userInteraction": "NONE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
                "version": "4.0",
                "vulnAvailabilityImpact": "HIGH",
                "vulnConfidentialityImpact": "HIGH",
                "vulnIntegrityImpact": "HIGH",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-787",
                  "description": "CWE-787",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-09-22T19:51:50.077Z",
            "orgId": "7d14cffa-0d7d-4270-9dc0-52cabd5a23a6",
            "shortName": "icscert"
          },
          "references": [
            {
              "url": "https://savannah.nongnu.org/projects/lwip"
            },
            {
              "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-01"
            },
            {
              "url": "https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-265-01.json"
            }
          ],
          "solutions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "Users of lwIP are encouraged to update their version of lwIP using the repository found at\u0026nbsp;\u003ca href=\"https://savannah.nongnu.org/projects/lwip\"\u003ehttps://savannah.nongnu.org/projects/lwip\u003c/a\u003e. The commit identifier that contains the fix is f89407ea711879c04d91c92b35d67be78bbaf0f1."
                }
              ],
              "value": "Users of lwIP are encouraged to update their version of lwIP using the repository found at\u00a0 https://savannah.nongnu.org/projects/lwip . The commit identifier that contains the fix is f89407ea711879c04d91c92b35d67be78bbaf0f1."
            }
          ],
          "source": {
            "advisory": "ICSA-26-265-01",
            "discovery": "EXTERNAL"
          },
          "title": "Out-of-bounds write in lwIP TCP/IP Stack MQTT Client Application",
          "x_generator": {
            "engine": "Vulnogram 1.0.5"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "7d14cffa-0d7d-4270-9dc0-52cabd5a23a6",
        "assignerShortName": "icscert",
        "cveId": "CVE-2026-87121",
        "datePublished": "2026-09-22T19:48:25.046Z",
        "dateReserved": "2026-09-09T21:28:27.099Z",
        "dateUpdated": "2026-09-22T20:23:09.069Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

FKIE_CVE-2026-87121

Vulnerability from fkie_nvd - Published: 2026-09-22 20:17 - Updated: 2026-09-23 19:42

Severity

9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

lwIP TCP/IP Stack MQTT is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device.

References

	URL	Tags
	ics-cert@hq.dhs.gov	https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-265-01.json
	ics-cert@hq.dhs.gov	https://savannah.nongnu.org/projects/lwip
	ics-cert@hq.dhs.gov	https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-01

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "TCP/IP Stack MQTT",
          "vendor": "lwIP",
          "versions": [
            {
              "lessThanOrEqual": "2.2.1",
              "status": "affected",
              "version": "2.0.1",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "ics-cert@hq.dhs.gov"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "lwIP\u00a0TCP/IP Stack MQTT\u00a0is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device."
    }
  ],
  "id": "CVE-2026-87121",
  "lastModified": "2026-09-23T19:42:48.540",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "ics-cert@hq.dhs.gov",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 9.3,
          "baseSeverity": "CRITICAL",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "HIGH",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "ics-cert@hq.dhs.gov",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-87121",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-22T20:23:00.531481Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-22T20:17:09.967",
  "references": [
    {
      "source": "ics-cert@hq.dhs.gov",
      "url": "https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-265-01.json"
    },
    {
      "source": "ics-cert@hq.dhs.gov",
      "url": "https://savannah.nongnu.org/projects/lwip"
    },
    {
      "source": "ics-cert@hq.dhs.gov",
      "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-01"
    }
  ],
  "sourceIdentifier": "ics-cert@hq.dhs.gov",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-787"
        }
      ],
      "source": "ics-cert@hq.dhs.gov",
      "type": "Secondary"
    }
  ]
}

GHSA-H8Q6-7RJX-3M2R

Vulnerability from github – Published: 2026-09-22 21:31 – Updated: 2026-09-22 21:31

Details

lwIP TCP/IP Stack MQTT is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device.

Severity

9.8 (Critical)


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

9.3 (Critical)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-87121"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-787"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-22T20:17:09Z",
    "severity": "CRITICAL"
  },
  "details": "lwIP\u00a0TCP/IP Stack MQTT\u00a0is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device.",
  "id": "GHSA-h8q6-7rjx-3m2r",
  "modified": "2026-09-22T21:31:29Z",
  "published": "2026-09-22T21:31:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-87121"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-265-01.json"
    },
    {
      "type": "WEB",
      "url": "https://savannah.nongnu.org/projects/lwip"
    },
    {
      "type": "WEB",
      "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-01"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

ICSA-26-265-01

Vulnerability from csaf_cisa - Published: 2026-09-22 06:00 - Updated: 2026-09-22 06:00

Summary

lwIP TCP/IP Stack MQTT Client Application

Scope

1 vulnerability in this advisory, including CVE-2026-87121.

CVE-2026-87121

9.8 (Critical)


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

Known affected: 1 product

https://savannah.nongnu.org/projects/lwip

Open the full advisory

UBUNTU-CVE-2026-87121 (CVE-2026-87121)

Vulnerability from osv_ubuntu – Published: 2026-09-22 20:17 – Updated: 2026-10-17 09:54 – Source website

Details

lwIP TCP/IP Stack MQTT is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device.

Severity

9.8 (Critical)


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

9.3 (Critical)


                    
                      CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-87121	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-87121	REPORT
	https://github.com/cisagov/CSAF/blob/develop/csaf…	REPORT
	https://savannah.nongnu.org/projects/lwip	REPORT
	https://www.cisa.gov/news-events/ics-advisories/i…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "liblwip0",
            "binary_version": "2.1.2+dfsg1-4ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "lwip",
        "purl": "pkg:deb/ubuntu/lwip@2.1.2+dfsg1-4ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.1.2-3",
        "2.1.2-5.1",
        "2.1.2+dfsg1-1",
        "2.1.2+dfsg1-4",
        "2.1.2+dfsg1-4ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "liblwip0",
            "binary_version": "2.1.3+dfsg1-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:22.04:LTS",
        "name": "lwip",
        "purl": "pkg:deb/ubuntu/lwip@2.1.3+dfsg1-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.1.2+dfsg1-8",
        "2.1.2+dfsg1-9",
        "2.1.3+dfsg1-1",
        "2.1.3+dfsg1-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "liblwip0t64",
            "binary_version": "2.2.0+dfsg1-6.1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "lwip",
        "purl": "pkg:deb/ubuntu/lwip@2.2.0+dfsg1-6.1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.1.3+dfsg1-2",
        "2.1.3+dfsg1-4",
        "2.2.0+dfsg1-2",
        "2.2.0+dfsg1-3",
        "2.2.0+dfsg1-4",
        "2.2.0+dfsg1-5",
        "2.2.0+dfsg1-6",
        "2.2.0+dfsg1-6.1",
        "2.2.0+dfsg1-6.1build1",
        "2.2.0+dfsg1-6.1build2",
        "2.2.0+dfsg1-6.1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "liblwip0t64",
            "binary_version": "2.2.1+dfsg1-7"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.10",
        "name": "lwip",
        "purl": "pkg:deb/ubuntu/lwip@2.2.1+dfsg1-7?arch=source\u0026distro=stonking"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.2.1+dfsg1-4",
        "2.2.1+dfsg1-5",
        "2.2.1+dfsg1-7"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "liblwip0t64",
            "binary_version": "2.2.1+dfsg1-4ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:26.04:LTS",
        "name": "lwip",
        "purl": "pkg:deb/ubuntu/lwip@2.2.1+dfsg1-4ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.2.1+dfsg1-2",
        "2.2.1+dfsg1-3",
        "2.2.1+dfsg1-4",
        "2.2.1+dfsg1-4ubuntu0.1~esm1"
      ]
    }
  ],
  "aliases": [],
  "details": "lwIP\u00a0TCP/IP Stack MQTT\u00a0is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device.",
  "id": "UBUNTU-CVE-2026-87121",
  "modified": "2026-10-17T09:54:15Z",
  "published": "2026-09-22T20:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-87121"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-87121"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-265-01.json"
    },
    {
      "type": "REPORT",
      "url": "https://savannah.nongnu.org/projects/lwip"
    },
    {
      "type": "REPORT",
      "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-01"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-87121"
  ]
}

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

Order JSON

How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Publication & reservation Sightings KEV catalogs Other timestamps

Loading timeline…

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-87121 (GCVE-0-2026-87121)

FKIE_CVE-2026-87121

GHSA-H8Q6-7RJX-3M2R

ICSA-26-265-01

UBUNTU-CVE-2026-87121 (CVE-2026-87121)

Tags

Sightings

Nomenclature

Vulnerability timeline

Related by attack behaviour