Vulnerability-Lookup

ubuntu-cve-2026-18916

Vulnerability from osv_ubuntu

Published

2026-08-26 09:16

Modified

2026-09-02 16:12

Summary

Details

Any remote client can crash a NSD serve child, by throttling the TCP receive window after a TCP query. By continuously crashing the serve childs, the remote client can denial all TCP service to this NSD instance.

Severity

6.9 (Medium)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-18916	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-18916	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "nsd",
            "binary_version": "4.1.7-1ubuntu0.1~esm1"
          },
          {
            "binary_name": "nsd3",
            "binary_version": "4.1.7-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "nsd",
        "purl": "pkg:deb/ubuntu/nsd@4.1.7-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps-legacy/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.1.2-1",
        "4.1.6-1",
        "4.1.7-1",
        "4.1.7-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "nsd",
            "binary_version": "4.1.17-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "nsd",
        "purl": "pkg:deb/ubuntu/nsd@4.1.17-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.1.16-1build1",
        "4.1.17-1",
        "4.1.17-1build1",
        "4.1.17-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "nsd",
            "binary_version": "4.1.26-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "nsd",
        "purl": "pkg:deb/ubuntu/nsd@4.1.26-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.1.26-1",
        "4.1.26-1build1",
        "4.1.26-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "nsd",
            "binary_version": "4.3.9-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:22.04:LTS",
        "name": "nsd",
        "purl": "pkg:deb/ubuntu/nsd@4.3.9-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.3.5-1",
        "4.3.7-1",
        "4.3.8-1",
        "4.3.8-1build1",
        "4.3.9-1",
        "4.3.9-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "nsd",
            "binary_version": "4.8.0-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "nsd",
        "purl": "pkg:deb/ubuntu/nsd@4.8.0-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.7.0-1",
        "4.8.0-1",
        "4.8.0-1build1",
        "4.8.0-1build3",
        "4.8.0-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "nsd",
            "binary_version": "4.14.0-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:26.04:LTS",
        "name": "nsd",
        "purl": "pkg:deb/ubuntu/nsd@4.14.0-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.12.0-1",
        "4.13.0-6",
        "4.14.0-1",
        "4.14.0-1ubuntu0.1~esm1"
      ]
    }
  ],
  "aliases": [],
  "details": "Any remote client can crash a NSD serve child, by throttling the TCP receive window after a TCP query. By continuously crashing the serve childs, the remote client can denial all TCP service to this NSD instance.",
  "id": "UBUNTU-CVE-2026-18916",
  "modified": "2026-09-02T16:12:08Z",
  "published": "2026-08-26T09:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-18916"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-18916"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-18916"
  ]
}

CVE-2026-18916 (GCVE-0-2026-18916)

Vulnerability from cvelistv5 – Published: 2026-08-26 08:39 – Updated: 2026-08-26 14:22

Title

Remote TCP DoS by throttling the TCP receive window

Summary

Severity

6.9 (Medium)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-26 14:17 UTC

CWE

CWE-191 - Integer Underflow

Assigner

NLnet Labs

References

1 reference

URL	Tags
https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-1…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
NLnet Labs	NSD	Affected: 3.2.11 , < 4.15.1 (semver)

Date Public

2026-08-26 12:00

Credits

Akhil Koul (https://github.com/akoul)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-18916",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-26T14:17:49.150057Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-26T14:22:31.309Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "NSD",
          "vendor": "NLnet Labs",
          "versions": [
            {
              "lessThan": "4.15.1",
              "status": "affected",
              "version": "3.2.11",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Akhil Koul (https://github.com/akoul)"
        }
      ],
      "datePublic": "2026-08-26T12:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "Any remote client can crash a NSD serve child, by throttling the TCP receive window after a TCP query. By continuously crashing the serve childs, the remote client can denial all TCP service to this NSD instance."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "baseScore": 6.9,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
            "version": "4.0"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "Remote client denying TCP availability by throttling the TCP receive window (down to 1 byte)"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-191",
              "description": "CWE-191: Integer Underflow",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-26T08:39:12.258Z",
        "orgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
        "shortName": "NLnet Labs"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-18916.txt"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "This issue is fixed in 4.15.1 and all later versions."
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-08-01T00:02:43.000Z",
          "value": "Issue reported by Akhil Koul"
        },
        {
          "lang": "en",
          "time": "2026-08-05T07:39:41.000Z",
          "value": "NLnet Labs shares patch"
        },
        {
          "lang": "en",
          "time": "2026-08-05T14:18:42.000Z",
          "value": "Akhil Koul verifies patch"
        },
        {
          "lang": "en",
          "time": "2026-08-26T12:00:00.000Z",
          "value": "Fix released with version 4.15.1"
        }
      ],
      "title": "Remote TCP DoS by throttling the TCP receive window",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
    "assignerShortName": "NLnet Labs",
    "cveId": "CVE-2026-18916",
    "datePublished": "2026-08-26T08:39:12.258Z",
    "dateReserved": "2026-08-05T07:36:55.457Z",
    "dateUpdated": "2026-08-26T14:22:31.309Z",
    "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.

Detection rules are retrieved from Rulezet.

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.