{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-40777",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-07-18T14:25:41.033326Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-07-18T14:25:48.883Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "BIND 9",
          "vendor": "ISC",
          "versions": [
            {
              "lessThanOrEqual": "9.20.10",
              "status": "affected",
              "version": "9.20.0",
              "versionType": "custom"
            },
            {
              "lessThanOrEqual": "9.21.9",
              "status": "affected",
              "version": "9.21.0",
              "versionType": "custom"
            },
            {
              "lessThanOrEqual": "9.20.10-S1",
              "status": "affected",
              "version": "9.20.9-S1",
              "versionType": "custom"
            },
            {
              "lessThanOrEqual": "9.18.37",
              "status": "unaffected",
              "version": "9.18.0",
              "versionType": "custom"
            },
            {
              "lessThanOrEqual": "9.18.37-S1",
              "status": "unaffected",
              "version": "9.18.11-S1",
              "versionType": "custom"
            }
          ]
        }
      ],
      "datePublic": "2025-07-16T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "If a `named` caching resolver is configured with `serve-stale-enable` `yes`, and with `stale-answer-client-timeout` set to `0` (the only allowable value other than `disabled`), and if the resolver, in the process of resolving a query, encounters a CNAME chain involving a specific combination of cached or authoritative records, the daemon will abort with an assertion failure.\nThis issue affects BIND 9 versions 9.20.0 through 9.20.10, 9.21.0 through 9.21.9, and 9.20.9-S1 through 9.20.10-S1."
        }
      ],
      "exploits": [
        {
          "lang": "en",
          "value": "This flaw was discovered in internal testing. We are not aware of any active exploits."
        }
      ],
      "impacts": [
        {
          "descriptions": [
            {
              "lang": "en",
              "value": "If an attacker is able to make queries that yield the necessary combination of circumstances, they can force `named` to exit."
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-617",
              "description": "CWE-617 Reachable Assertion",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-07-16T17:38:06.370Z",
        "orgId": "404fd4d2-a609-4245-b543-2c944a302a22",
        "shortName": "isc"
      },
      "references": [
        {
          "name": "CVE-2025-40777",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://kb.isc.org/docs/cve-2025-40777"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Upgrade to the patched release most closely related to your current version of BIND 9: 9.20.11, 9.21.10, or 9.20.11-S1."
        }
      ],
      "source": {
        "discovery": "INTERNAL"
      },
      "title": "A possible assertion failure when \u0027stale-answer-client-timeout\u0027 is set to \u00270\u0027",
      "workarounds": [
        {
          "lang": "en",
          "value": "Setting either of `stale-answer-client-timeout off;` or `stale-answer-enable no;` in the configuration file will prevent the assertion."
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "404fd4d2-a609-4245-b543-2c944a302a22",
    "assignerShortName": "isc",
    "cveId": "CVE-2025-40777",
    "datePublished": "2025-07-16T17:38:06.370Z",
    "dateReserved": "2025-04-16T08:44:49.856Z",
    "dateUpdated": "2025-07-18T14:25:48.883Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-40777\",\"sourceIdentifier\":\"security-officer@isc.org\",\"published\":\"2025-07-16T18:15:24.770\",\"lastModified\":\"2025-07-17T21:15:50.197\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"If a `named` caching resolver is configured with `serve-stale-enable` `yes`, and with `stale-answer-client-timeout` set to `0` (the only allowable value other than `disabled`), and if the resolver, in the process of resolving a query, encounters a CNAME chain involving a specific combination of cached or authoritative records, the daemon will abort with an assertion failure.\\nThis issue affects BIND 9 versions 9.20.0 through 9.20.10, 9.21.0 through 9.21.9, and 9.20.9-S1 through 9.20.10-S1.\"},{\"lang\":\"es\",\"value\":\"Si un solucionador de cach\u00e9 con nombre est\u00e1 configurado con `serve-stale-enable` `yes` y con `stale-answer-client-timeout` establecido en `0` (el \u00fanico valor permitido aparte de `disabled`), y si el solucionador, al resolver una consulta, encuentra una cadena CNAME que involucra una combinaci\u00f3n espec\u00edfica de registros en cach\u00e9 o autorizados, el daemon se interrumpir\u00e1 con un error de aserci\u00f3n. Este problema afecta a las versiones de BIND 9 de la 9.20.0 a la 9.20.10, de la 9.21.0 a la 9.21.9 y de la 9.20.9-S1 a la 9.20.10-S1.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-officer@isc.org\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"security-officer@isc.org\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-617\"}]}],\"references\":[{\"url\":\"https://kb.isc.org/docs/cve-2025-40777\",\"source\":\"security-officer@isc.org\"}]}}"
  }
}