ubuntu-cve-2026-11605
Vulnerability from osv_ubuntu
Published
2026-07-22 15:16
Modified
2026-08-19 16:13
Summary
Details

The issue is a resource exhaustion vulnerability associated with DNSSEC validation. BIND always validates all RRSIG records in an answer, even if they are not strictly needed. A query to an authoritative server/zone which returns many valid but superfluous RRSIG records causes the validator to waste disproportionate CPU time. This issue affects BIND 9 versions 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, and 9.20.9-S1 through 9.20.24-S1.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "bind9",
            "binary_version": "1:9.20.24-1ubuntu0.2"
          },
          {
            "binary_name": "bind9-dnsutils",
            "binary_version": "1:9.20.24-1ubuntu0.2"
          },
          {
            "binary_name": "bind9-host",
            "binary_version": "1:9.20.24-1ubuntu0.2"
          },
          {
            "binary_name": "bind9-libs",
            "binary_version": "1:9.20.24-1ubuntu0.2"
          },
          {
            "binary_name": "bind9-utils",
            "binary_version": "1:9.20.24-1ubuntu0.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "bind9",
        "purl": "pkg:deb/ubuntu/bind9@1:9.20.24-1ubuntu0.2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:9.20.24-1ubuntu0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:9.20.11-1ubuntu2",
        "1:9.20.11-1ubuntu3",
        "1:9.20.18-1ubuntu1",
        "1:9.20.18-1ubuntu2",
        "1:9.20.18-1ubuntu2.1",
        "1:9.20.24-1ubuntu0.1"
      ]
    }
  ],
  "aliases": [],
  "details": "The issue is a resource exhaustion vulnerability associated with DNSSEC validation. BIND always validates all RRSIG records in an answer, even if they are not strictly needed. A query to an authoritative server/zone which returns many valid but superfluous RRSIG records causes the validator to waste disproportionate CPU time. This issue affects BIND 9 versions 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, and 9.20.9-S1 through 9.20.24-S1.",
  "id": "UBUNTU-CVE-2026-11605",
  "modified": "2026-08-19T16:13:16Z",
  "published": "2026-07-22T15:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-11605"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-11605"
    },
    {
      "type": "REPORT",
      "url": "https://kb.isc.org/docs/cve-2026-11605"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8648-1"
    }
  ],
  "related": [
    "USN-8648-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-11605"
  ]
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.