Security advisory

{
  "id": "b469b3413a190d26e3d8e7147249edb23298d34fd7636320ebb69bb8054189aa",
  "url": "https://osv.dev/vulnerability/CVE-2026-50243",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2026-50243",
    "summary": "In NLnet Labs Unbound 1.6.2 up to and including 1.25.1, when Unbound is configured with the 'respip' module in front of the validator together with a 'response-ip' redirect rule or an RPZ file with an RPZ-IP trigger, the rewriting handler does not check the security status of the upstream answer and can instead rewrite a BOGUS A/AAAA answer to point to an operator's configured IP. If the validator finds an expired or otherwise invalid RRSIG on an answer whose A record falls within a 'response-ip'/RPZ configuration, the answer is still rewritten and given a hard coded security level of INSECURE. This results in the client receiving an INSECURE NOERROR reply rewritten by the operator's configured IP. A malicious actor can exploit the possible poisonous effect by spoofing a BOGUS A/AAAA answer that falls inside the operator's configured subnet rewrites. Such DNSSEC protected answers are then insecurely redirected to the operator's configured target.",
    "evidence": "osv:CVE-2026-50243",
    "products": [],
    "severity": "low",
    "structured": {
      "id": "CVE-2026-50243",
      "aliases": [
        "CVE-2026-50243"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/nlnetlabs/unbound",
              "type": "GIT",
              "events": [
                {
                  "introduced": "93732890aaae9ced2d55ce13b12ce01dc06d9e31"
                },
                {
                  "fixed": "c33ad1b1a21e48bfe4f140e90252a9be1b0c5745"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.6.2"
                      },
                      {
                        "fixed": "1.25.2"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-50243.json"
          }
        }
      ],
      "modified": "2026-10-26T02:31:00.719155497Z",
      "provider": "osv",
      "references": [
        "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-50243.txt"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2026-50243",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 446685,
  "published_at": "2026-07-22T14:17:20.24+00:00"
}