Quadratic bignum parsing of Content-Length and Host port values in Bandit

{
  "id": "30a61dddc31f21abaa7b3df8a8919173c422dc003649e2824139d9679b37b76a",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-113436",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Quadratic bignum parsing of Content-Length and Host port values in Bandit",
    "summary": "Inefficient Algorithmic Complexity vulnerability in the header integer parser of mtrudel bandit allows an unauthenticated remote attacker to consume server CPU via a content-length value or a Host or :authority port made of thousands of digits. Bandit.Headers.parse_integer/2 in lib/bandit/headers.ex builds the number one digit at a time with no limit on the digit count, allocating a new bignum at each step, so one value costs time quadratic in its length. It runs on raw request input over HTTP/1 and HTTP/2, before any range check. Over HTTP/2, a 4,000-digit value can be stored once in the HPACK dynamic table and re-sent on each new stream for about one byte: 124 KB of traffic kept the server busy for 27.9 s. This issue affects bandit: from 1.0.0-pre.7 before 1.14.0.",
    "evidence": "cve:CVE-2026-113436",
    "products": [
      {
        "name": {
          "value": "bandit",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      },
      {
        "name": {
          "value": "bandit",
          "evidence": "/containers/cna/affected/1/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-113436",
      "aliases": [
        "CVE-2026-113436"
      ],
      "metrics": [
        {
          "format": "CVSS",
          "cvssV4_0": {
            "Safety": "NOT_DEFINED",
            "version": "4.0",
            "Recovery": "NOT_DEFINED",
            "baseScore": 8.7,
            "Automatable": "NOT_DEFINED",
            "attackVector": "NETWORK",
            "baseSeverity": "HIGH",
            "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",
            "providerUrgency": "NOT_DEFINED",
            "userInteraction": "NONE",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "privilegesRequired": "NONE",
            "subIntegrityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "HIGH",
            "subConfidentialityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "affected": [
        {
          "cpes": [
            "cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*"
          ],
          "repo": "https://github.com/mtrudel/bandit",
          "vendor": "mtrudel",
          "product": "bandit",
          "versions": [
            {
              "status": "affected",
              "version": "1.0.0-pre.7",
              "lessThan": "1.14.0",
              "versionType": "semver"
            }
          ],
          "packageURL": "pkg:hex/bandit",
          "packageName": "bandit",
          "collectionURL": "https://repo.hex.pm",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*"
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          "repo": "https://github.com/mtrudel/bandit",
          "vendor": "mtrudel",
          "product": "bandit",
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              "version": "e0c8c0c30af9b0f57d8aafac37ddd9294363a8be",
              "lessThan": "220b9dfd27f9a21305be2afc75cbe585ddc24e7a",
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          ],
          "packageURL": "pkg:github/mtrudel/bandit",
          "packageName": "mtrudel/bandit",
          "collectionURL": "https://github.com",
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-26T15:35:51.556Z",
      "provider": "cve",
      "references": [
        "https://github.com/mtrudel/bandit/security/advisories/GHSA-29cr-8477-rg6r",
        "https://cna.erlef.org/cves/CVE-2026-113436.html",
        "https://osv.dev/vulnerability/EEF-CVE-2026-113436",
        "https://github.com/mtrudel/bandit/commit/e0c8c0c30af9b0f57d8aafac37ddd9294363a8be",
        "https://github.com/mtrudel/bandit/commit/220b9dfd27f9a21305be2afc75cbe585ddc24e7a"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-113436",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-10-26T15:12:04.626946Z"
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              "shortName": "CISA-ADP",
              "dateUpdated": "2026-10-26T15:35:51.556Z"
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        "cna": {
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          "shortName": "EEF",
          "dateUpdated": "2026-10-26T13:31:35.033Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-113436",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 316044,
  "published_at": "2026-10-26T13:31:35.033+00:00"
}