CVE-2026-113431

{
  "id": "CVE-2026-113431",
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
  "published": "2026-11-06T11:17:04.410",
  "lastModified": "2026-11-06T11:17:04.410",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Allocation of Resources Without Limits or Throttling vulnerability in ninenines cowlib allows an unauthenticated remote peer to exhaust the memory of an HTTP/2 endpoint via HPACK-indexed header fields.\n\ncow_http2_machine:headers_decode/4 in src/cow_http2_machine.erl decodes every HEADERS block with cow_hpack:decode/3. It bounds the compressed block size and the number of fields, but not the size of the decoded header list that RFC 9113 section 6.5.2 places under SETTINGS_MAX_HEADER_LIST_SIZE. A peer stores one header value of up to the dynamic table size (4096 bytes by default) and then references it with one-byte indexed fields, so about 100 bytes on the wire decode to a header list of about 390 KB. A consumer that copies the decoded values, as Cowboy does when cowboy_http2:headers_to_map/2 joins repeated cookie fields into one binary, allocates that amount for every stream. The total across streams and connections is not bounded.\n\nThis issue affects cowlib: from 2.7.0 onward."
    }
  ],
  "affected": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "affectedData": [
        {
          "vendor": "ninenines",
          "product": "cowlib",
          "defaultStatus": "unaffected",
          "collectionURL": "https://repo.hex.pm",
          "packageName": "cowlib",
          "cpes": [
            "cpe:2.3:a:ninenines:cowlib:*:*:*:*:*:*:*:*"
          ],
          "modules": [
            "cow_http2_machine",
            "cow_hpack"
          ],
          "programFiles": [
            "src/cow_http2_machine.erl",
            "src/cow_hpack.erl"
          ],
          "programRoutines": [
            {
              "name": "cow_http2_machine:headers_decode/4"
            },
            {
              "name": "cow_http2_machine:frame/2"
            },
            {
              "name": "cow_hpack:decode/3"
            },
            {
              "name": "cow_hpack:decode/2"
            }
          ],
          "repo": "https://github.com/ninenines/cowlib",
          "packageURL": "pkg:hex/cowlib",
          "versions": [
            {
              "version": "2.7.0",
              "lessThan": "*",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "ninenines",
          "product": "cowlib",
          "defaultStatus": "unaffected",
          "collectionURL": "https://github.com",
          "packageName": "ninenines/cowlib",
          "cpes": [
            "cpe:2.3:a:ninenines:cowlib:*:*:*:*:*:*:*:*"
          ],
          "modules": [
            "cow_http2_machine",
            "cow_hpack"
          ],
          "programFiles": [
            "src/cow_http2_machine.erl",
            "src/cow_hpack.erl"
          ],
          "programRoutines": [
            {
              "name": "cow_http2_machine:headers_decode/4"
            },
            {
              "name": "cow_http2_machine:frame/2"
            },
            {
              "name": "cow_hpack:decode/3"
            },
            {
              "name": "cow_hpack:decode/2"
            }
          ],
          "repo": "https://github.com/ninenines/cowlib",
          "packageURL": "pkg:github/ninenines/cowlib",
          "versions": [
            {
              "version": "b461b119e78e4e09bb28b186b09da7ed4a86a0dd",
              "lessThan": "a3b15e29b3067644bfd580246c87f7af7a90b3b8",
              "versionType": "git",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "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"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://cna.erlef.org/cves/CVE-2026-113431.html",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/ninenines/cowlib/commit/a3b15e29b3067644bfd580246c87f7af7a90b3b8",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/ninenines/cowlib/commit/b461b119e78e4e09bb28b186b09da7ed4a86a0dd",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-113431",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    }
  ]
}