{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "1.19.1"
              },
              {
                "fixed": "1.25.1"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "c6dd1e116df75242a0c032295c152f06c721b3cd"
            },
            {
              "fixed": "75b6dba593d4fff000434cd64807c6ebd50bd244"
            }
          ],
          "repo": "https://github.com/nlnetlabs/unbound",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {},
  "details": "NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.",
  "id": "CVE-2026-33278",
  "modified": "2026-07-08T05:39:19.770050831Z",
  "published": "2026-05-20T10:16:26.530Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-33278"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33278.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:19752"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:23231"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:24369"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-33278.txt"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2479808"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}