{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "CoreDNS is a DNS server that chains plugins. In versions prior to 1.14.3, the DNS-over-QUIC (DoQ) server can be driven into unbounded goroutine and memory growth by a remote client that opens many QUIC streams and sends only 1 byte per stream. When the worker pool is full, CoreDNS still spawns a goroutine per accepted stream to wait for a worker token. Additionally, active workers block indefinitely in io.ReadFull() with no per-stream read deadline, allowing an attacker to pin all workers by sending a single byte so the read blocks waiting for the second byte of the DoQ length prefix. This enables an unauthenticated remote attacker to cause memory exhaustion and OOM-kill. This issue has been fixed in version 1.14.3. No known workarounds exist."
    }
  ],
  "id": "CVE-2026-32934",
  "lastModified": "2026-05-05T20:16:35.853",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 8.7,
          "baseSeverity": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "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",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-05-05T20:16:35.853",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/coredns/coredns/releases/tag/v1.14.3"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/coredns/coredns/security/advisories/GHSA-2wpx-qpw2-g5h5"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/coredns/coredns"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.14.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-32934"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-28T22:40:38Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\nCoreDNS\u0027 DNS-over-QUIC (DoQ) server can be driven into large goroutine and memory growth by a remote client that opens many QUIC streams and stalls after sending only 1 byte. Even with a small configured quic { worker_pool_size ... }, CoreDNS still spawns a goroutine per accepted stream (workers + waiters) and active workers can block indefinitely in io.ReadFull() with no per-stream read deadline, enabling unauthenticated remote DoS via memory exhaustion/OOM-kill.\n\n### Details\nCoreDNS\u0027 DoQ server uses a global worker pool (streamProcessPool) to limit concurrent stream processing, but when the pool is full it still spawns a goroutine per accepted stream that waits to acquire a worker token: select { case s.streamProcessPool \u003c- ...: go ...; default: go ... wait for token ... } (core/dnsserver/server_quic.go)\n\nAdditionally, the DoQ message framing reads are blocking io.ReadFull() calls with no per-stream read deadline: readDOQMessage() reads the 2-byte length prefix and message body via io.ReadFull() (core/dnsserver/server_quic.go)\n\nThis allows an attacker to pin all workers by sending 1 byte (so io.ReadFull() blocks waiting for the second byte of the DoQ length prefix), while also creating an unbounded backlog of goroutines waiting for a worker token.\n\nNote: this appears to be a result of an incomplete fix/regression for CVE-2025-47950 (GHSA-cvx7-x8pj-x2gw).\n\n### PoC\n1. Adjust COREDNS_BIN in the PoC to point at right path (see the top-level const definitions for tunables as well)\n2. Run python3 ./doq-dos-repro.py\n3. Expected sample output:\n*** Start CoreDNS ***\nCorefile: /tmp/vh-f003-doq-mem-regression/Corefile\nLog: /tmp/vh-f003-doq-mem-regression/coredns.log\n\n*** Baseline sample (idle) ***\nrss_kib=49380 go_goroutines=17\n\n*** Build + run partial-stream flooder ***\ngo: downloading golang.org/x/net v0.43.0\ngo: downloading golang.org/x/crypto v0.41.0\ngo: downloading go.uber.org/mock v0.5.2\ngo: downloading github.com/stretchr/testify v1.11.1\ngo: downloading golang.org/x/sys v0.35.0\ngo: downloading github.com/pmezard/go-difflib v1.0.0\ngo: downloading github.com/davecgh/go-spew v1.1.1\ngo: downloading gopkg.in/yaml.v3 v3.0.1\n\n*** Candidate sample (during attack) ***\nrss_kib=137968 go_goroutines=15557\n\n*** Flooder output ***\nopened conns=60 streams_per_conn=256 total_streams=15360\n\n*** Wrote results ***\n/tmp/vh-f003-doq-mem-regression/results.json\n\n*** OK ***\nDoQ flood caused goroutine/RSS growth despite worker_pool_size.\n\n\n### Impact\nUnauthenticated remote DoS on an encrypted DNS transport via goroutine/RSS growth leading to OOM-kill/crash and service outage.",
  "id": "GHSA-2wpx-qpw2-g5h5",
  "modified": "2026-04-28T22:40:38Z",
  "published": "2026-04-28T22:40:38Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/coredns/coredns/security/advisories/GHSA-2wpx-qpw2-g5h5"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coredns/coredns/security/advisories/GHSA-cvx7-x8pj-x2gw"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/coredns/coredns"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coredns/coredns/releases/tag/v1.14.3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "CoreDNS\u0027 DoQ worker pool does not bound stream backlog"
}