{
  "containers": {
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      "affected": [
        {
          "product": "cpp-httplib",
          "vendor": "yhirose",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.43.4"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.43.4, negative chunk-size in chunked Transfer-Encoding causes unbounded memory allocation and process crash. The ChunkedDecoder::read_payload function in cpp-httplib (httplib.h) parses the chunk-size field of HTTP chunked transfer encoding using std::strtoul(). Per the C standard (\u00a77.22.1.4), strtoul silently accepts a leading minus sign, performing unsigned wrap-around: strtoul(\"-2\", \u2026, 16) returns ULONG_MAX \u2212 1 (0xFFFFFFFFFFFFFFFE). The library\u0027s only guard (line 12833) rejects ULONG_MAX (the result of \"-1\"), but any other negative value such as \"-2\" passes validation. The resulting near-maximum value is stored in chunk_remaining and controls how many bytes the server\u0027s read loop consumes from the network. This vulnerability is fixed in 0.43.4."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "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:L",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-20",
              "description": "CWE-20: Improper Input Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-1285",
              "description": "CWE-1285: Improper Validation of Specified Index, Position, or Offset in Input",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-770",
              "description": "CWE-770: Allocation of Resources Without Limits or Throttling",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-29T19:15:42.208Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-h6wq-j5mv-f3q8",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-h6wq-j5mv-f3q8"
        }
      ],
      "source": {
        "advisory": "GHSA-h6wq-j5mv-f3q8",
        "discovery": "UNKNOWN"
      },
      "title": "cpp-httplib DoS: Negative chunk-size in chunked Transfer-Encoding"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-45352",
    "datePublished": "2026-05-29T19:14:08.065Z",
    "dateReserved": "2026-05-11T21:40:08.178Z",
    "dateUpdated": "2026-05-29T19:15:42.208Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-45352\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-05-29T20:16:26.140\",\"lastModified\":\"2026-05-29T20:23:08.683\",\"vulnStatus\":\"Undergoing Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.43.4, negative chunk-size in chunked Transfer-Encoding causes unbounded memory allocation and process crash. The ChunkedDecoder::read_payload function in cpp-httplib (httplib.h) parses the chunk-size field of HTTP chunked transfer encoding using std::strtoul(). Per the C standard (\u00a77.22.1.4), strtoul silently accepts a leading minus sign, performing unsigned wrap-around: strtoul(\\\"-2\\\", \u2026, 16) returns ULONG_MAX \u2212 1 (0xFFFFFFFFFFFFFFFE). The library\u0027s only guard (line 12833) rejects ULONG_MAX (the result of \\\"-1\\\"), but any other negative value such as \\\"-2\\\" passes validation. The resulting near-maximum value is stored in chunk_remaining and controls how many bytes the server\u0027s read loop consumes from the network. This vulnerability is fixed in 0.43.4.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L\",\"baseScore\":5.3,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"LOW\"},\"exploitabilityScore\":3.9,\"impactScore\":1.4}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-20\"},{\"lang\":\"en\",\"value\":\"CWE-770\"},{\"lang\":\"en\",\"value\":\"CWE-1285\"}]}],\"references\":[{\"url\":\"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-h6wq-j5mv-f3q8\",\"source\":\"security-advisories@github.com\"}]}}"
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}