{
  "cveId": "CVE-2026-44687",
  "url": "https://patchblox.com/security/cve/CVE-2026-44687",
  "summary": "CVE-2026-44687 is fixed in 12 products on 1 platform, first by DEBIAN-CVE-2026-44687, released July 28, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "Off-by-one error in \u0027harden-below-nxdomain\u0027 logic can shadow a stub/forward zone by a legitimate parent\u0027s NXDOMAIN",
  "description": "In NLnet Labs Unbound 1.13.2 up to and including 1.25.1, stub or forward zones where the name is below an intermediate labed below a DNSSEC signed zone could be shadowed by the intermediate label\u0027s secure NXDOMAIN answer from the parent. This is caused by an off-by-one error in \u0027harden-below-nxdomain\u0027 logic; enabled by default. It effectively bypasses the configuration and the configured stub/forward zone is never contacted. \u0027harden-below-nxdomain\u0027 does an upward DNS cache walk together with a delegation point guard that does not allow NXDOMAIN synthesis above stub/forward zones. The guard tests the domain name but before stripping a label. This results in an iteration where the domain name equals the configured stub/forward zone apex that passes the guard, strips one more label, and probes the cache at the apex\u0027s immediate public parent. If that parent has a cached DNSSEC-secure NXDOMAIN, which it will for any private namespace nested two or more labels under a signed public name, the walk returns it and the configured stub/forward upstream is never contacted. This can only be triggered by the query for the intermediate label (between the stub/forward apex and the DNSSEC parent zone).",
  "published": "2026-07-22T14:17:19Z",
  "severity": "Low",
  "cvss": 3.7,
  "cvssVector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L",
  "cwe": "Off-by-one Error",
  "epss": 0.00218,
  "epssPercentile": 0.12321,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-44687",
  "fixes": [
    {
      "platform": "linux",
      "product": "python3-unbound",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.13",
      "fix": "ALAS2023-2026-2033",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2033",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-unbound-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.13",
      "fix": "ALAS2023-2026-2033",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2033",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "1.26.1-0\u002Bdeb13u1",
      "fix": "DEBIAN-CVE-2026-44687",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-44687",
      "released": "2026-07-28T14:13:38Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "Debian 14",
      "fixedVersion": "1.25.2-1",
      "fix": "DEBIAN-CVE-2026-44687",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-44687",
      "released": "2026-07-28T14:13:38Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.13",
      "fix": "ALAS2023-2026-2033",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2033",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "opensuse-leap 16.0",
      "fixedVersion": "1.25.2-160000.1.1",
      "fix": "OPENSUSE-SU-2026:21550-1",
      "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-21550-1",
      "released": "2026-08-10T15:27:28Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "sles 15.6",
      "fixedVersion": "1.25.2-150600.23.19.1",
      "fix": "SUSE-SU-2026:3885-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-3885-1",
      "released": "2026-08-31T14:34:37Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "sles 15.7",
      "fixedVersion": "1.25.2-150600.23.19.1",
      "fix": "SUSE-SU-2026:3885-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-3885-1",
      "released": "2026-08-31T14:34:37Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "sles 16.0",
      "fixedVersion": "1.25.2-160000.1.1",
      "fix": "SUSE-SU-2026:23226-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-23226-1",
      "released": "2026-08-10T15:26:22Z"
    },
    {
      "platform": "linux",
      "product": "unbound-anchor",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.13",
      "fix": "ALAS2023-2026-2033",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2033",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-anchor-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.13",
      "fix": "ALAS2023-2026-2033",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2033",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.13",
      "fix": "ALAS2023-2026-2033",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2033",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-debugsource",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.13",
      "fix": "ALAS2023-2026-2033",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2033",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-devel",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.13",
      "fix": "ALAS2023-2026-2033",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2033",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-libs",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.13",
      "fix": "ALAS2023-2026-2033",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2033",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-libs-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.13",
      "fix": "ALAS2023-2026-2033",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2033",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-utils",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.13",
      "fix": "ALAS2023-2026-2033",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2033",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "unbound-utils-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1.17.1-1.amzn2023.0.13",
      "fix": "ALAS2023-2026-2033",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2033",
      "released": "2026-08-03T09:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T19:38:12Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}