{
  "cveId": "CVE-2026-78227",
  "url": "https://patchblox.com/security/cve/CVE-2026-78227",
  "summary": "CVE-2026-78227 is fixed in unbound on 1 platform, first by DEBIAN-CVE-2026-78227, released September 19, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "Use-after-free in DoQ stream output buffer on reset re-transmission",
  "description": "NLnet Labs Unbound 1.22.0 up to and including 1.26.1, has a use-after-free vulnerability when compiled for DNS-over-QUIC support with \u0027--with-libngtcp2\u0027. Each DoQ stream owns an output buffer that holds the DNS response. ngtcp2\u0027s retransmission buffer keeps a shallow pointer into the output buffer for as long as a STREAM frame may be resent. On a client RESET_STREAM, the output buffer is freed but ngtcp2 still holds the matching retransmission entries. The next PTO timeout makes ngtcp2 re-encode the STREAM frame and copy from the freed buffer. A malicious actor that can query Unbound over DoQ and that withholds ACKs, sends RESET_STREAM, and waits for PTO, reaches this use-after-free with no privilege. This leads to retransmissions against freed memory and eventually an abnormal server exit under a 20-query spray.",
  "published": "2026-09-16T09:17:05Z",
  "severity": "Moderate",
  "cvss": 6.5,
  "cvssVector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:L",
  "cwe": "Use After Free",
  "epss": 0.0034,
  "epssPercentile": 0.2761,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78227",
  "fixes": [
    {
      "platform": "linux",
      "product": "unbound",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "1.26.1-0\u002Bdeb13u1",
      "fix": "DEBIAN-CVE-2026-78227",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-78227",
      "released": "2026-09-19T18:30:58Z"
    },
    {
      "platform": "linux",
      "product": "unbound",
      "release": "Debian 14",
      "fixedVersion": "1.26.1-1",
      "fix": "DEBIAN-CVE-2026-78227",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-78227",
      "released": "2026-09-19T18:30:58Z"
    },
    {
      "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"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T19:12:23Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}