cve-2026-80225

MEDIUM CVSS 5.3 fkie_nvd

Description

In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT connection, monopolizes a single worker's entire event loop for as long as its writes stay ahead of the drain.

Timeline

Published: unknown
Last Modified: unknown

CVSS Details

Attack Vector: NETWORK
Attack Complexity: LOW
Privileges Required: NONE

Affected Products

nlnetlabs unbound

Weaknesses (CWE)

CWE-770

CVSS metrics

Version	Base	Severity	Vector	Exploitability	Impact	Source
3.1	5.3	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`	3.9	1.4	sep@nlnetlabs.nl
3.1	7.5	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`	3.9	3.6	nvd@nist.gov

CPE configurations

CPE	Version range	Vulnerable
`cpe:2.3:a:nlnetlabs:unbound::::::::`	< 1.26.1	yes

NVD metadata

NVD status: Analyzed
Source identifier: sep@nlnetlabs.nl

References

https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-80225.txt Patch, Vendor Advisory

Linked Vulnerabilities

azurelinux3-101724 azure_linux

3f4d285d-b1f6-11f1-8f5e-3c7c3fba4204 freebsd

fedora-2026-3baacede89 fedora

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Unbound",
          "vendor": "NLnet Labs",
          "versions": [
            {
              "lessThan": "1.26.1",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "sep@nlnetlabs.nl"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "EFE466C2-2830-48B5-AD1D-0138CB8207A7",
              "versionEndExcluding": "1.26.1",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT connection, monopolizes a single worker's entire event loop for as long as its writes stay ahead of the drain."
    }
  ],
  "id": "CVE-2026-80225",
  "lastModified": "2026-09-23T19:57:08.517",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "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:L",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4,
        "source": "sep@nlnetlabs.nl",
        "type": "Secondary"
      },
      {
        "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": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-80225",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-16T14:32:57.188145Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-16T09:17:06.100",
  "references": [
    {
      "source": "sep@nlnetlabs.nl",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-80225.txt"
    }
  ],
  "sourceIdentifier": "sep@nlnetlabs.nl",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ],
      "source": "sep@nlnetlabs.nl",
      "type": "Secondary"
    }
  ]
}

cve-2026-80225

Raw JSON Data