CVE-2026-32936 (GCVE-0-2026-32936)

Vulnerability from cvelistv5 – Published: 2026-05-05 19:07 – Updated: 2026-05-05 19:32
VLAI
Title
CoreDNS DoH GET path missing size validation causes CPU and memory amplification
Summary
CoreDNS is a DNS server that chains plugins. In versions prior to 1.14.3, the DNS-over-HTTPS (DoH) GET path accepts oversized dns= query parameter values and performs URL query parsing, base64 decoding, and DNS message unpacking before rejecting the request. Unlike the POST path, which applies a bounded read via http.MaxBytesReader limited to 65536 bytes, the GET path has no equivalent size validation before expensive processing. A remote, unauthenticated attacker can repeatedly send oversized DoH GET requests to force high CPU usage, large transient memory allocations, and elevated garbage-collection pressure, leading to denial of service. This issue has been fixed in version 1.14.3.
Severity
8.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-400 - Uncontrolled Resource Consumption
Assigner
References
Impacted products
Vendor Product Version
coredns coredns Affected: < 1.14.3
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-32936",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-05T19:32:21.653054Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-05T19:32:25.341Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/coredns/coredns/security/advisories/GHSA-63cw-r7xf-jmwr"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "coredns",
          "vendor": "coredns",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.14.3"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "CoreDNS is a DNS server that chains plugins. In versions prior to 1.14.3, the DNS-over-HTTPS (DoH) GET path accepts oversized dns= query parameter values and performs URL query parsing, base64 decoding, and DNS message unpacking before rejecting the request. Unlike the POST path, which applies a bounded read via http.MaxBytesReader limited to 65536 bytes, the GET path has no equivalent size validation before expensive processing. A remote, unauthenticated attacker can repeatedly send oversized DoH GET requests to force high CPU usage, large transient memory allocations, and elevated garbage-collection pressure, leading to denial of service. This issue has been fixed in version 1.14.3."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-400",
              "description": "CWE-400: Uncontrolled Resource Consumption",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-05T19:07:51.926Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/coredns/coredns/security/advisories/GHSA-63cw-r7xf-jmwr",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/coredns/coredns/security/advisories/GHSA-63cw-r7xf-jmwr"
        },
        {
          "name": "https://github.com/coredns/coredns/releases/tag/v1.14.3",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/coredns/coredns/releases/tag/v1.14.3"
        }
      ],
      "source": {
        "advisory": "GHSA-63cw-r7xf-jmwr",
        "discovery": "UNKNOWN"
      },
      "title": "CoreDNS DoH GET path missing size validation causes CPU and memory amplification"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-32936",
    "datePublished": "2026-05-05T19:07:51.926Z",
    "dateReserved": "2026-03-17T00:05:53.282Z",
    "dateUpdated": "2026-05-05T19:32:25.341Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-32936",
      "date": "2026-07-26",
      "epss": "0.00672",
      "percentile": "0.48304"
    },
    "microsoft_vex": {
      "current_release_date": "2026-05-15T14:40:06.000Z",
      "cve": "CVE-2026-32936",
      "id": "msrc_CVE-2026-32936",
      "initial_release_date": "2026-05-02T00:00:00.000Z",
      "product_status:fixed": "1",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "CoreDNS DoH GET path missing size validation causes CPU and memory amplification",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-32936.json",
      "version": "2"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-32936\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-05-05T20:16:36.010\",\"lastModified\":\"2026-07-25T11:10:00.100\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"CoreDNS is a DNS server that chains plugins. In versions prior to 1.14.3, the DNS-over-HTTPS (DoH) GET path accepts oversized dns= query parameter values and performs URL query parsing, base64 decoding, and DNS message unpacking before rejecting the request. Unlike the POST path, which applies a bounded read via http.MaxBytesReader limited to 65536 bytes, the GET path has no equivalent size validation before expensive processing. A remote, unauthenticated attacker can repeatedly send oversized DoH GET requests to force high CPU usage, large transient memory allocations, and elevated garbage-collection pressure, leading to denial of service. This issue has been fixed in version 1.14.3.\"},{\"lang\":\"es\",\"value\":\"CoreDNS es un servidor DNS que encadena complementos. En versiones anteriores a la 1.14.3, la ruta GET de DNS-over-HTTPS (DoH) acepta valores de par\u00e1metros de consulta \u0027dns=\u0027 sobredimensionados y realiza el an\u00e1lisis de la consulta URL, la decodificaci\u00f3n base64 y el desempaquetado del mensaje DNS antes de rechazar la solicitud. A diferencia de la ruta POST, que aplica una lectura acotada a trav\u00e9s de http.MaxBytesReader limitada a 65536 bytes, la ruta GET no tiene una validaci\u00f3n de tama\u00f1o equivalente antes de un procesamiento costoso. Un atacante remoto no autenticado puede enviar repetidamente solicitudes GET de DoH sobredimensionadas para forzar un alto uso de CPU, grandes asignaciones de memoria transitoria y una presi\u00f3n elevada de recolecci\u00f3n de basura, lo que lleva a una denegaci\u00f3n de servicio. Este problema ha sido solucionado en la versi\u00f3n 1.14.3.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"coredns\",\"product\":\"coredns\",\"versions\":[{\"version\":\"\u003c 1.14.3\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X\",\"baseScore\":8.7,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"NONE\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"NONE\",\"vulnIntegrityImpact\":\"NONE\",\"vulnAvailabilityImpact\":\"HIGH\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"NONE\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}],\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"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}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-05-05T19:32:21.653054Z\",\"id\":\"CVE-2026-32936\",\"options\":[{\"exploitation\":\"poc\"},{\"automatable\":\"yes\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-400\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:coredns.io:coredns:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"1.14.3\",\"matchCriteriaId\":\"0B1F8FE2-314C-4C38-9F18-099ACCFF0AAD\"}]}]}],\"references\":[{\"url\":\"https://github.com/coredns/coredns/releases/tag/v1.14.3\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Release Notes\"]},{\"url\":\"https://github.com/coredns/coredns/security/advisories/GHSA-63cw-r7xf-jmwr\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Exploit\",\"Mitigation\",\"Vendor Advisory\"]},{\"url\":\"https://github.com/coredns/coredns/security/advisories/GHSA-63cw-r7xf-jmwr\",\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"tags\":[\"Exploit\",\"Mitigation\",\"Vendor Advisory\"]}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-06-28T11:48:09+00:00",
      "cve": "CVE-2026-32936",
      "id": "CVE-2026-32936",
      "initial_release_date": "2026-05-05T19:07:51.926000+00:00",
      "product_status:fixed": "8",
      "product_status:known_not_affected": "26",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "github.com/coredns/coredns: CoreDNS: Denial of Service via oversized DNS-over-HTTPS GET requests",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-32936.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-06-27T02:01:59Z",
      "cve": "CVE-2026-32936",
      "id": "CVE-2026-32936",
      "initial_release_date": "2026-05-07T02:21:00Z",
      "product_status:recommended": "2",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-32936",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-32936.json",
      "version": "4"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-32936\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"poc\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-05-05T19:32:21.653054Z\"}}}], \"references\": [{\"url\": \"https://github.com/coredns/coredns/security/advisories/GHSA-63cw-r7xf-jmwr\", \"tags\": [\"exploit\"]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-05-05T19:32:10.408Z\"}}], \"cna\": {\"title\": \"CoreDNS DoH GET path missing size validation causes CPU and memory amplification\", \"source\": {\"advisory\": \"GHSA-63cw-r7xf-jmwr\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV4_0\": {\"version\": \"4.0\", \"baseScore\": 8.7, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"attackRequirements\": \"NONE\", \"privilegesRequired\": \"NONE\", \"subIntegrityImpact\": \"NONE\", \"vulnIntegrityImpact\": \"NONE\", \"subAvailabilityImpact\": \"NONE\", \"vulnAvailabilityImpact\": \"HIGH\", \"subConfidentialityImpact\": \"NONE\", \"vulnConfidentialityImpact\": \"NONE\"}}], \"affected\": [{\"vendor\": \"coredns\", \"product\": \"coredns\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 1.14.3\"}]}], \"references\": [{\"url\": \"https://github.com/coredns/coredns/security/advisories/GHSA-63cw-r7xf-jmwr\", \"name\": \"https://github.com/coredns/coredns/security/advisories/GHSA-63cw-r7xf-jmwr\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/coredns/coredns/releases/tag/v1.14.3\", \"name\": \"https://github.com/coredns/coredns/releases/tag/v1.14.3\", \"tags\": [\"x_refsource_MISC\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"CoreDNS is a DNS server that chains plugins. In versions prior to 1.14.3, the DNS-over-HTTPS (DoH) GET path accepts oversized dns= query parameter values and performs URL query parsing, base64 decoding, and DNS message unpacking before rejecting the request. Unlike the POST path, which applies a bounded read via http.MaxBytesReader limited to 65536 bytes, the GET path has no equivalent size validation before expensive processing. A remote, unauthenticated attacker can repeatedly send oversized DoH GET requests to force high CPU usage, large transient memory allocations, and elevated garbage-collection pressure, leading to denial of service. This issue has been fixed in version 1.14.3.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-400\", \"description\": \"CWE-400: Uncontrolled Resource Consumption\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-05-05T19:07:51.926Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-32936\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-05-05T19:32:25.341Z\", \"dateReserved\": \"2026-03-17T00:05:53.282Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-05-05T19:07:51.926Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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

Author Source Type Date Other

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.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • 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.