{
  "cveId": "CVE-2026-85501",
  "url": "https://patchblox.com/security/cve/CVE-2026-85501",
  "summary": "CVE-2026-85501 is fixed in 16 products on 1 platform, first by libunbound2 1.6.7-1ubuntu2.6\u002Besm6, released September 16, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "Retrap: Novel Vulnerabilities to launch Algorithmic Complexity Attacks on DNSSEC",
  "description": "Novel vulnerabilities to launch algorithmic complexity attacks on DNSSEC have been researched under the term \u0027ReTrap\u0027. These result in degradation of service when malicious zones are used to serve the algorithmic complexity vulnerabilities. NLnet Labs Unbound up to and including 1.26.0 is vulnerable to some of them. TagTrap, where  the triple(Zone, Algo, KeyTag) matching mechanism introduces a significant attack vector when resolvers handle malicious responses containing numerous mismatched DNSKEY, RRSIG, and DS record. DelegationTrap, where constructing the chain-of-trust requires iterative validation of DNSKEY and DS records from the root zone downward. For deeply nested domains, this results in significant computational overhead. NsecTrap, where  responses with excessive invalid NSEC records compel the resolver to validate each one. AdditionalTrap, where Unbound by default would try to DNSSEC validate the ADDITIONAL section as well. This can be exploited to waste validation resources by malicious users.",
  "published": "2026-09-16T02:17:00Z",
  "severity": "Moderate",
  "cvss": 7.5,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
  "cwe": "Allocation of Resources Without Limits or Throttling",
  "epss": 0.00482,
  "epssPercentile": 0.41805,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85501",
  "fixes": [
    {
      "platform": "linux",
      "product": "libunbound2",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1.6.7-1ubuntu2.6\u002Besm6",
      "fix": "libunbound2 1.6.7-1ubuntu2.6\u002Besm6",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-libunbound2-1.6.7-1ubuntu2.6-esm6",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "libunbound8",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.9.4-2ubuntu1.11\u002Besm3",
      "fix": "libunbound8 1.9.4-2ubuntu1.11\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libunbound8-1.9.4-2ubuntu1.11-esm3",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "libunbound8",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "1.13.1-1ubuntu5.17",
      "fix": "libunbound8 1.13.1-1ubuntu5.17",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-libunbound8-1.13.1-1ubuntu5.17",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "libunbound8",
      "release": "Ubuntu 24.04.5 LTS (noble)",
      "fixedVersion": "1.19.2-1ubuntu3.12",
      "fix": "libunbound8 1.19.2-1ubuntu3.12",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-noble-libunbound8-1.19.2-1ubuntu3.12",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "libunbound8",
      "release": "Ubuntu 26.04.1 LTS (resolute)",
      "fixedVersion": "1.24.2-1ubuntu2.4",
      "fix": "libunbound8 1.24.2-1ubuntu2.4",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-resolute-libunbound8-1.24.2-1ubuntu2.4",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "python-unbound",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1.6.7-1ubuntu2.6\u002Besm6",
      "fix": "python-unbound 1.6.7-1ubuntu2.6\u002Besm6",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-python-unbound-1.6.7-1ubuntu2.6-esm6",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "python-unbound",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.9.4-2ubuntu1.11\u002Besm3",
      "fix": "python-unbound 1.9.4-2ubuntu1.11\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-python-unbound-1.9.4-2ubuntu1.11-esm3",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-unbound",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1.6.7-1ubuntu2.6\u002Besm6",
      "fix": "python3-unbound 1.6.7-1ubuntu2.6\u002Besm6",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-python3-unbound-1.6.7-1ubuntu2.6-esm6",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-unbound",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.9.4-2ubuntu1.11\u002Besm3",
      "fix": "python3-unbound 1.9.4-2ubuntu1.11\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-python3-unbound-1.9.4-2ubuntu1.11-esm3",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-unbound",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "1.13.1-1ubuntu5.17",
      "fix": "python3-unbound 1.13.1-1ubuntu5.17",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-python3-unbound-1.13.1-1ubuntu5.17",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-unbound",
      "release": "Ubuntu 24.04.5 LTS (noble)",
      "fixedVersion": "1.19.2-1ubuntu3.12",
      "fix": "python3-unbound 1.19.2-1ubuntu3.12",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-noble-python3-unbound-1.19.2-1ubuntu3.12",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-unbound",
      "release": "Ubuntu 26.04.1 LTS (resolute)",
      "fixedVersion": "1.24.2-1ubuntu2.4",
      "fix": "python3-unbound 1.24.2-1ubuntu2.4",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-resolute-python3-unbound-1.24.2-1ubuntu2.4",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-unbound",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.15",
      "fix": "ALAS2023-2026-3127",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3127",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-unbound-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.15",
      "fix": "ALAS2023-2026-3127",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3127",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "1.26.1-0\u002Bdeb13u1",
      "fix": "DEBIAN-CVE-2026-85501",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-85501",
      "released": "2026-09-19T18:30:58Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "Debian 14",
      "fixedVersion": "1.26.1-1",
      "fix": "DEBIAN-CVE-2026-85501",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-85501",
      "released": "2026-09-19T18:30:58Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1.6.7-1ubuntu2.6\u002Besm6",
      "fix": "unbound 1.6.7-1ubuntu2.6\u002Besm6",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-unbound-1.6.7-1ubuntu2.6-esm6",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.9.4-2ubuntu1.11\u002Besm3",
      "fix": "unbound 1.9.4-2ubuntu1.11\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-unbound-1.9.4-2ubuntu1.11-esm3",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "1.13.1-1ubuntu5.17",
      "fix": "unbound 1.13.1-1ubuntu5.17",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-unbound-1.13.1-1ubuntu5.17",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "Ubuntu 24.04.5 LTS (noble)",
      "fixedVersion": "1.19.2-1ubuntu3.12",
      "fix": "unbound 1.19.2-1ubuntu3.12",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-noble-unbound-1.19.2-1ubuntu3.12",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "Ubuntu 26.04.1 LTS (resolute)",
      "fixedVersion": "1.24.2-1ubuntu2.4",
      "fix": "unbound 1.24.2-1ubuntu2.4",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-resolute-unbound-1.24.2-1ubuntu2.4",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.15",
      "fix": "ALAS2023-2026-3127",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3127",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "opensuse-leap 16.0",
      "fixedVersion": "1.26.1-160000.1.1",
      "fix": "OPENSUSE-SU-2026:22082-1",
      "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-22082-1",
      "released": "2026-11-07T00:48:28Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "sles 15.6",
      "fixedVersion": "1.26.1-150600.23.24.1",
      "fix": "SUSE-SU-2026:4620-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-4620-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "sles 15.7",
      "fixedVersion": "1.26.1-150600.23.24.1",
      "fix": "SUSE-SU-2026:4620-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-4620-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "sles 16.0",
      "fixedVersion": "1.26.1-160000.1.1",
      "fix": "SUSE-SU-2026:24226-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-24226-1",
      "released": "2026-11-07T00:45:20Z"
    },
    {
      "platform": "linux",
      "product": "unbound-anchor",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1.6.7-1ubuntu2.6\u002Besm6",
      "fix": "unbound-anchor 1.6.7-1ubuntu2.6\u002Besm6",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-unbound-anchor-1.6.7-1ubuntu2.6-esm6",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-anchor",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.9.4-2ubuntu1.11\u002Besm3",
      "fix": "unbound-anchor 1.9.4-2ubuntu1.11\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-unbound-anchor-1.9.4-2ubuntu1.11-esm3",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-anchor",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "1.13.1-1ubuntu5.17",
      "fix": "unbound-anchor 1.13.1-1ubuntu5.17",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-unbound-anchor-1.13.1-1ubuntu5.17",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-anchor",
      "release": "Ubuntu 24.04.5 LTS (noble)",
      "fixedVersion": "1.19.2-1ubuntu3.12",
      "fix": "unbound-anchor 1.19.2-1ubuntu3.12",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-noble-unbound-anchor-1.19.2-1ubuntu3.12",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-anchor",
      "release": "Ubuntu 26.04.1 LTS (resolute)",
      "fixedVersion": "1.24.2-1ubuntu2.4",
      "fix": "unbound-anchor 1.24.2-1ubuntu2.4",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-resolute-unbound-anchor-1.24.2-1ubuntu2.4",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-anchor",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.15",
      "fix": "ALAS2023-2026-3127",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3127",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-anchor-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.15",
      "fix": "ALAS2023-2026-3127",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3127",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.15",
      "fix": "ALAS2023-2026-3127",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3127",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-debugsource",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.15",
      "fix": "ALAS2023-2026-3127",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3127",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-devel",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.15",
      "fix": "ALAS2023-2026-3127",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3127",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-host",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1.6.7-1ubuntu2.6\u002Besm6",
      "fix": "unbound-host 1.6.7-1ubuntu2.6\u002Besm6",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-unbound-host-1.6.7-1ubuntu2.6-esm6",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-host",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.9.4-2ubuntu1.11\u002Besm3",
      "fix": "unbound-host 1.9.4-2ubuntu1.11\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-unbound-host-1.9.4-2ubuntu1.11-esm3",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-host",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "1.13.1-1ubuntu5.17",
      "fix": "unbound-host 1.13.1-1ubuntu5.17",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-unbound-host-1.13.1-1ubuntu5.17",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-host",
      "release": "Ubuntu 24.04.5 LTS (noble)",
      "fixedVersion": "1.19.2-1ubuntu3.12",
      "fix": "unbound-host 1.19.2-1ubuntu3.12",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-noble-unbound-host-1.19.2-1ubuntu3.12",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-host",
      "release": "Ubuntu 26.04.1 LTS (resolute)",
      "fixedVersion": "1.24.2-1ubuntu2.4",
      "fix": "unbound-host 1.24.2-1ubuntu2.4",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-resolute-unbound-host-1.24.2-1ubuntu2.4",
      "released": "2026-09-16T02:17:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-libs",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.15",
      "fix": "ALAS2023-2026-3127",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3127",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-libs-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.15",
      "fix": "ALAS2023-2026-3127",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3127",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-utils",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.15",
      "fix": "ALAS2023-2026-3127",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3127",
      "released": "2026-09-28T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-utils-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.15",
      "fix": "ALAS2023-2026-3127",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3127",
      "released": "2026-09-28T09:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}