{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "1.12.0"
              },
              {
                "fixed": "1.26.1"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "52b04806f4236c37acd10179ab465a54adc7e86a"
            },
            {
              "fixed": "13b6717f1716810523ffb60f971a6c9c5e8ce127"
            }
          ],
          "repo": "https://github.com/nlnetlabs/unbound",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {},
  "details": "NLnet Labs Unbound 1.12.0 up to and including 1.26.0 has a use-after-free vulnerability when compiled for DNS-over-HTTPs support with '--with-libnghttp2'. During failure code paths (i.e., RPZ drop query, jostle due to heavy traffic), a dropped DoH stream brings down the whole DoH session and does not account properly for other DoH streams in the same session. This leads to use-after-free in those code paths. If the prerequisites are satisfied (possible RPZ drop or heavy client traffic), a malicious actor can trigger the vulnerability with a single DoH connection and the appropriate traffic. Impact is limited as the reads are not user controlled and the use-after-free leads to early returns. However, a hardened allocator can catch the use-after-free and controllably terminate the process resulting to denial of service.",
  "id": "CVE-2026-82720",
  "modified": "2026-09-25T03:30:35.709743494Z",
  "published": "2026-09-16T09:17:06.677Z",
  "references": [
    {
      "type": "FIX",
      "url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-82720.txt"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}