Vulnerability-Lookup

OESA-2026-4130 (CVE-2026-81642)

Vulnerability from osv_openeuler – Published: 2026-09-25 01:28 – Updated: 2026-09-25 01:28 – Source website

Summary

unbound security update

Details

Unbound is a validating, recursive, caching DNS resolver. It is designed to be fast and lean and incorporates modern features based on open standards. To help increase online privacy, Unbound supports DNS-over-TLS which allows clients to encrypt their communication. Unbound is available for most platforms such as FreeBSD, OpenBSD, NetBSD, MacOS, Linux and Microsoft Windows. Unbound is a totally free, open source software under the BSD license. It doesn't make custom builds or provide specific features to paying customers only.

Security Fix(es):

In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in the DNSSEC validator that enables denial of service and possible remote code execution as a result of digesting DNSKEYs. A DNSKEY with an owner compression pointer to its own RDATA can overflow the digest buffer. Remote code execution is possible through attacker controlled data. An adversary can exploit the vulnerability by controlling a malicious zone and querying a vulnerable Unbound.(CVE-2026-81642)

Severity

9.1 (Critical)


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

References

URL

Type

	https://www.openeuler.org/zh/security/security-bu…	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2026-81642	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "aarch64": [
          "python3-unbound-1.17.1-21.oe2403sp4.aarch64.rpm",
          "unbound-1.17.1-21.oe2403sp4.aarch64.rpm",
          "unbound-anchor-1.17.1-21.oe2403sp4.aarch64.rpm",
          "unbound-debuginfo-1.17.1-21.oe2403sp4.aarch64.rpm",
          "unbound-debugsource-1.17.1-21.oe2403sp4.aarch64.rpm",
          "unbound-devel-1.17.1-21.oe2403sp4.aarch64.rpm",
          "unbound-help-1.17.1-21.oe2403sp4.aarch64.rpm",
          "unbound-libs-1.17.1-21.oe2403sp4.aarch64.rpm",
          "unbound-utils-1.17.1-21.oe2403sp4.aarch64.rpm"
        ],
        "src": [
          "unbound-1.17.1-21.oe2403sp4.src.rpm"
        ],
        "x86_64": [
          "python3-unbound-1.17.1-21.oe2403sp4.x86_64.rpm",
          "unbound-1.17.1-21.oe2403sp4.x86_64.rpm",
          "unbound-anchor-1.17.1-21.oe2403sp4.x86_64.rpm",
          "unbound-debuginfo-1.17.1-21.oe2403sp4.x86_64.rpm",
          "unbound-debugsource-1.17.1-21.oe2403sp4.x86_64.rpm",
          "unbound-devel-1.17.1-21.oe2403sp4.x86_64.rpm",
          "unbound-help-1.17.1-21.oe2403sp4.x86_64.rpm",
          "unbound-libs-1.17.1-21.oe2403sp4.x86_64.rpm",
          "unbound-utils-1.17.1-21.oe2403sp4.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:24.03-LTS-SP4",
        "name": "unbound",
        "purl": "pkg:rpm/openEuler/unbound\u0026distro=openEuler-24.03-LTS-SP4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.17.1-21.oe2403sp4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "aarch64": [
          "python3-unbound-1.11.0-27.oe2003sp4.aarch64.rpm",
          "unbound-1.11.0-27.oe2003sp4.aarch64.rpm",
          "unbound-debuginfo-1.11.0-27.oe2003sp4.aarch64.rpm",
          "unbound-debugsource-1.11.0-27.oe2003sp4.aarch64.rpm",
          "unbound-devel-1.11.0-27.oe2003sp4.aarch64.rpm",
          "unbound-help-1.11.0-27.oe2003sp4.aarch64.rpm",
          "unbound-libs-1.11.0-27.oe2003sp4.aarch64.rpm"
        ],
        "src": [
          "unbound-1.11.0-27.oe2003sp4.src.rpm"
        ],
        "x86_64": [
          "python3-unbound-1.11.0-27.oe2003sp4.x86_64.rpm",
          "unbound-1.11.0-27.oe2003sp4.x86_64.rpm",
          "unbound-debuginfo-1.11.0-27.oe2003sp4.x86_64.rpm",
          "unbound-debugsource-1.11.0-27.oe2003sp4.x86_64.rpm",
          "unbound-devel-1.11.0-27.oe2003sp4.x86_64.rpm",
          "unbound-help-1.11.0-27.oe2003sp4.x86_64.rpm",
          "unbound-libs-1.11.0-27.oe2003sp4.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:20.03-LTS-SP4",
        "name": "unbound",
        "purl": "pkg:rpm/openEuler/unbound\u0026distro=openEuler-20.03-LTS-SP4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.11.0-27.oe2003sp4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "aarch64": [
          "python3-unbound-1.13.2-27.oe2203sp4.aarch64.rpm",
          "unbound-1.13.2-27.oe2203sp4.aarch64.rpm",
          "unbound-anchor-1.13.2-27.oe2203sp4.aarch64.rpm",
          "unbound-debuginfo-1.13.2-27.oe2203sp4.aarch64.rpm",
          "unbound-debugsource-1.13.2-27.oe2203sp4.aarch64.rpm",
          "unbound-devel-1.13.2-27.oe2203sp4.aarch64.rpm",
          "unbound-help-1.13.2-27.oe2203sp4.aarch64.rpm",
          "unbound-libs-1.13.2-27.oe2203sp4.aarch64.rpm"
        ],
        "src": [
          "unbound-1.13.2-27.oe2203sp4.src.rpm"
        ],
        "x86_64": [
          "python3-unbound-1.13.2-27.oe2203sp4.x86_64.rpm",
          "unbound-1.13.2-27.oe2203sp4.x86_64.rpm",
          "unbound-anchor-1.13.2-27.oe2203sp4.x86_64.rpm",
          "unbound-debuginfo-1.13.2-27.oe2203sp4.x86_64.rpm",
          "unbound-debugsource-1.13.2-27.oe2203sp4.x86_64.rpm",
          "unbound-devel-1.13.2-27.oe2203sp4.x86_64.rpm",
          "unbound-help-1.13.2-27.oe2203sp4.x86_64.rpm",
          "unbound-libs-1.13.2-27.oe2203sp4.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:22.03-LTS-SP4",
        "name": "unbound",
        "purl": "pkg:rpm/openEuler/unbound\u0026distro=openEuler-22.03-LTS-SP4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.13.2-27.oe2203sp4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "aarch64": [
          "python3-unbound-1.17.1-21.oe2403sp1.aarch64.rpm",
          "unbound-1.17.1-21.oe2403sp1.aarch64.rpm",
          "unbound-anchor-1.17.1-21.oe2403sp1.aarch64.rpm",
          "unbound-debuginfo-1.17.1-21.oe2403sp1.aarch64.rpm",
          "unbound-debugsource-1.17.1-21.oe2403sp1.aarch64.rpm",
          "unbound-devel-1.17.1-21.oe2403sp1.aarch64.rpm",
          "unbound-help-1.17.1-21.oe2403sp1.aarch64.rpm",
          "unbound-libs-1.17.1-21.oe2403sp1.aarch64.rpm",
          "unbound-utils-1.17.1-21.oe2403sp1.aarch64.rpm"
        ],
        "src": [
          "unbound-1.17.1-21.oe2403sp1.src.rpm"
        ],
        "x86_64": [
          "python3-unbound-1.17.1-21.oe2403sp1.x86_64.rpm",
          "unbound-1.17.1-21.oe2403sp1.x86_64.rpm",
          "unbound-anchor-1.17.1-21.oe2403sp1.x86_64.rpm",
          "unbound-debuginfo-1.17.1-21.oe2403sp1.x86_64.rpm",
          "unbound-debugsource-1.17.1-21.oe2403sp1.x86_64.rpm",
          "unbound-devel-1.17.1-21.oe2403sp1.x86_64.rpm",
          "unbound-help-1.17.1-21.oe2403sp1.x86_64.rpm",
          "unbound-libs-1.17.1-21.oe2403sp1.x86_64.rpm",
          "unbound-utils-1.17.1-21.oe2403sp1.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:24.03-LTS-SP1",
        "name": "unbound",
        "purl": "pkg:rpm/openEuler/unbound\u0026distro=openEuler-24.03-LTS-SP1"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.17.1-21.oe2403sp1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "aarch64": [
          "python3-unbound-1.17.1-21.oe2403sp3.aarch64.rpm",
          "unbound-1.17.1-21.oe2403sp3.aarch64.rpm",
          "unbound-anchor-1.17.1-21.oe2403sp3.aarch64.rpm",
          "unbound-debuginfo-1.17.1-21.oe2403sp3.aarch64.rpm",
          "unbound-debugsource-1.17.1-21.oe2403sp3.aarch64.rpm",
          "unbound-devel-1.17.1-21.oe2403sp3.aarch64.rpm",
          "unbound-help-1.17.1-21.oe2403sp3.aarch64.rpm",
          "unbound-libs-1.17.1-21.oe2403sp3.aarch64.rpm",
          "unbound-utils-1.17.1-21.oe2403sp3.aarch64.rpm"
        ],
        "src": [
          "unbound-1.17.1-21.oe2403sp3.src.rpm"
        ],
        "x86_64": [
          "python3-unbound-1.17.1-21.oe2403sp3.x86_64.rpm",
          "unbound-1.17.1-21.oe2403sp3.x86_64.rpm",
          "unbound-anchor-1.17.1-21.oe2403sp3.x86_64.rpm",
          "unbound-debuginfo-1.17.1-21.oe2403sp3.x86_64.rpm",
          "unbound-debugsource-1.17.1-21.oe2403sp3.x86_64.rpm",
          "unbound-devel-1.17.1-21.oe2403sp3.x86_64.rpm",
          "unbound-help-1.17.1-21.oe2403sp3.x86_64.rpm",
          "unbound-libs-1.17.1-21.oe2403sp3.x86_64.rpm",
          "unbound-utils-1.17.1-21.oe2403sp3.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:24.03-LTS-SP3",
        "name": "unbound",
        "purl": "pkg:rpm/openEuler/unbound\u0026distro=openEuler-24.03-LTS-SP3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.17.1-21.oe2403sp3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "severity": "Critical"
  },
  "details": "Unbound is a validating, recursive, caching DNS resolver. It is designed to be fast and lean and incorporates modern features based on open standards. To help increase online privacy, Unbound supports DNS-over-TLS which allows clients to encrypt their communication. Unbound is available for most platforms such as FreeBSD, OpenBSD, NetBSD, MacOS, Linux and Microsoft Windows. Unbound is a totally free, open source software under the BSD license. It doesn\u0026amp;apos;t make custom builds or provide specific features to paying customers only.\r\n\r\nSecurity Fix(es):\n\nIn NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in the DNSSEC validator that enables denial of service and possible remote code execution as a result of digesting DNSKEYs. A DNSKEY with an owner compression pointer to its own RDATA can overflow the digest buffer. Remote code execution is possible through attacker controlled data. An adversary can exploit the vulnerability by controlling a malicious zone and querying a vulnerable Unbound.(CVE-2026-81642)",
  "id": "OESA-2026-4130",
  "modified": "2026-09-25T01:28:51Z",
  "published": "2026-09-25T01:28:51Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-4130"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-81642"
    }
  ],
  "schema_version": "1.7.2",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:U/U:Red",
      "type": "CVSS_V4"
    }
  ],
  "summary": "unbound security update",
  "upstream": [
    "CVE-2026-81642"
  ]
}

CVE-2026-81642 (GCVE-0-2026-81642)

Vulnerability from cvelistv5 – Published: 2026-09-16 08:30 – Updated: 2026-09-16 14:32

Title

Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY

Summary

Severity

9.1 (Critical)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-16 14:30 UTC

CWE

CWE-122 - Heap-based Buffer Overflow

Assigner

NLnet Labs

References

1 reference

URL	Tags
https://www.nlnetlabs.nl/downloads/unbound/CVE-20…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
NLnet Labs	Unbound	Affected: 0 , < 1.26.1 (semver)

Date Public

2026-09-16 00:00

Credits

Yuqi Qiu (Nankai University, AOSP Lab) Xiang Li (Nankai University, AOSP Lab)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-81642",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-16T14:30:20.298477Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-16T14:32:16.825Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Unbound",
          "vendor": "NLnet Labs",
          "versions": [
            {
              "lessThan": "1.26.1",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Yuqi Qiu (Nankai University, AOSP Lab)"
        },
        {
          "lang": "en",
          "type": "finder",
          "value": "Xiang Li (Nankai University, AOSP Lab)"
        }
      ],
      "datePublic": "2026-09-16T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in the DNSSEC validator that enables denial of service and possible remote code execution as a result of digesting DNSKEYs. A DNSKEY with an owner compression pointer to its own RDATA can overflow the digest buffer. Remote code execution is possible through attacker controlled data. An adversary can exploit the vulnerability by controlling a malicious zone and querying a vulnerable Unbound."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:U/U:Red",
            "version": "4.0"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-122",
              "description": "CWE-122: Heap-based Buffer Overflow",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-16T08:30:58.604Z",
        "orgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
        "shortName": "NLnet Labs"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-81642.txt"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "This issue is fixed starting with version 1.26.1"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-08-11T00:00:00.000Z",
          "value": "Issue reported by Yuqi Qiu"
        },
        {
          "lang": "en",
          "time": "2026-08-12T00:00:00.000Z",
          "value": "NLnet Labs shares patch"
        },
        {
          "lang": "en",
          "time": "2026-08-13T00:00:00.000Z",
          "value": "Yuqi Qiu verifies patch"
        },
        {
          "lang": "en",
          "time": "2026-09-16T00:00:00.000Z",
          "value": "Fixes released with version 1.26.1"
        }
      ],
      "title": "Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
    "assignerShortName": "NLnet Labs",
    "cveId": "CVE-2026-81642",
    "datePublished": "2026-09-16T08:30:58.604Z",
    "dateReserved": "2026-09-07T14:06:21.956Z",
    "dateUpdated": "2026-09-16T14:32:16.825Z",
    "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.

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

OESA-2026-4130 (CVE-2026-81642)

CVE-2026-81642 (GCVE-0-2026-81642)

Tags

Sightings

Nomenclature

Related by attack behaviour