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Medium

httpc does not bound server-supplied numeric header values before integer conversion

Type: advisorySources: OSV

Improper Validation of Specified Quantity in Input vulnerability in Erlang/OTP inets httpc allows a malicious or compromised HTTP server to degrade availability by returning a numeric header whose value is a very long run of digits. httpc_handler.erl converts the server-supplied Content-Length with list_to_integer/1 before comparing it against max_body_size, so the size check cannot protect the conversion, and the option defaults to nolimit in any case. The same unbounded conversion appears in httpc_response:format_response/1 for Content-Length and in httpc_response:get_ms_from_retry_after/1 for Retry-After, which is guarded only by a check that the first character is a digit. A value of up to roughly 1.26 million digits converts successfully and costs the requesting process hundreds of milliseconds of arbitrary-precision arithmetic per response. The conversion function is documented to accept integers of any size, so bounding the input is the caller's responsibility. This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-71562
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 02:48 UTC · Revision 1

Source evidence

httpc does not bound server-supplied numeric header values before integer conversion

core-osv · Original source

Published 1 Sept 2026, 14:33 UTC

Improper Validation of Specified Quantity in Input vulnerability in Erlang/OTP inets httpc allows a malicious or compromised HTTP server to degrade availability by returning a numeric header whose value is a very long run of digits. httpc_handler.erl converts the server-supplied Content-Length with list_to_integer/1 before comparing it against max_body_size, so the size check cannot protect the conversion, and the option defaults to nolimit in any case. The same unbounded conversion appears in httpc_response:format_response/1 for Content-Length and in httpc_response:get_ms_from_retry_after/1 for Retry-After, which is guarded only by a check that the first character is a digit. A value of up to roughly 1.26 million digits converts successfully and costs the requesting process hundreds of milliseconds of arbitrary-precision arithmetic per response. The conversion function is documented to accept integers of any size, so bounding the input is the caller's responsibility. This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.

osv:CVE-2026-71562
Complete source record
{
  "id": "da3852b0d22f9e7d27b213526ff881e7bdf230e61a3a7dbfb5d22cd7a43d3d78",
  "url": "https://osv.dev/vulnerability/CVE-2026-71562",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "httpc does not bound server-supplied numeric header values before integer conversion",
    "summary": "Improper Validation of Specified Quantity in Input vulnerability in Erlang/OTP inets httpc allows a malicious or compromised HTTP server to degrade availability by returning a numeric header whose value is a very long run of digits. httpc_handler.erl converts the server-supplied Content-Length with list_to_integer/1 before comparing it against max_body_size, so the size check cannot protect the conversion, and the option defaults to nolimit in any case. The same unbounded conversion appears in httpc_response:format_response/1 for Content-Length and in httpc_response:get_ms_from_retry_after/1 for Retry-After, which is guarded only by a check that the first character is a digit. A value of up to roughly 1.26 million digits converts successfully and costs the requesting process hundreds of milliseconds of arbitrary-precision arithmetic per response. The conversion function is documented to accept integers of any size, so bounding the input is the caller's responsibility. This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.",
    "evidence": "osv:CVE-2026-71562",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-71562",
      "aliases": [
        "CVE-2026-71562",
        "EEF-CVE-2026-71562",
        "GHSA-cqx9-9hq6-m8wf"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/erlang/otp",
              "type": "GIT",
              "events": [
                {
                  "introduced": "84adefa331c4159d432d22840663c38f155cd4c1"
                },
                {
                  "fixed": "aba0fe8c2d700bf4ac94607cf7f00e53bbe4042d"
                },
                {
                  "introduced": "07b8f441ca711f9812fad9e9115bab3c3aa92f79"
                },
                {
                  "fixed": "79157f447019730504f6f6c43c9b1d1cfa1d4192"
                },
                {
                  "introduced": "9e6f6742c4d9e9915ee8af0dcb7d97cf1f836116"
                },
                {
                  "fixed": "e7252384d42f124c07bec5c79eebd7ea9cdd5100"
                },
                {
                  "introduced": "550d7b7898706c7822362c42e7b93120c1d1f29a"
                },
                {
                  "fixed": "e07fd07837e5aa845657f5fa340637121e451d47"
                },
                {
                  "fixed": "e3be1cfe9f6cedd0cd20d9905e05601dfb31c8aa"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "84adefa331c4159d432d22840663c38f155cd4c1"
                      },
                      {
                        "fixed": "aba0fe8c2d700bf4ac94607cf7f00e53bbe4042d"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "ChangesAt"
                  },
                  {
                    "range": [
                      {
                        "introduced": "17.0"
                      },
                      {
                        "fixed": "27.3.4.17"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "28.0"
                      },
                      {
                        "fixed": "28.5.0.6"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "29.0"
                      },
                      {
                        "fixed": "29.0.6"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "aba0fe8c2d700bf4ac94607cf7f00e53bbe4042d"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "e3be1cfe9f6cedd0cd20d9905e05601dfb31c8aa"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "patch-base-27",
            "OTP-27.3.4",
            "patch-base-28",
            "OTP-28.5",
            "OTP-29.0",
            "OTP-29.0.5",
            "OTP-27.3.4.9",
            "OTP-27.3.4.10",
            "OTP-29.0.2",
            "OTP-28.5.0.2",
            "OTP-28.5.0.5",
            "OTP-27.3.4.14",
            "OTP-27.3.4.16",
            "OTP-29.0.3",
            "OTP-27.3.4.15",
            "OTP-28.5.0.4",
            "OTP-29.0.4",
            "OTP-28.5.0.3",
            "OTP-27.3.4.13",
            "OTP-28.4",
            "OTP-27.3.4.12",
            "OTP-28.5.0.1",
            "OTP-29.0.1",
            "OTP-27.0",
            "OTP-27.3.4.11",
            "OTP-28.0",
            "OTP-27.3.4.8",
            "OTP-27.3.4.6",
            "OTP-27.3.4.7",
            "OTP-27.3",
            "OTP-27.3.4.5",
            "OTP-27.3.4.4",
            "OTP-28.1",
            "OTP-27.3.4.3",
            "OTP-27.3.3",
            "OTP-27.3.4.2",
            "OTP-26.0",
            "OTP-25.0",
            "OTP-27.3.4.1",
            "OTP-27.3.2",
            "OTP-27.2",
            "OTP-27.3.1",
            "OTP-27.1",
            "OTP-27.0-rc3",
            "OTP-27.0-rc2",
            "OTP-27.0-rc1",
            "OTP-24.0",
            "OTP-26.0-rc3",
            "OTP-26.0-rc2",
            "OTP-26.0-rc1",
            "OTP-23.0",
            "OTP-21.0",
            "OTP-25.0-rc3",
            "OTP-25.0-rc2",
            "OTP-25.0-rc1",
            "OTP-22.0",
            "OTP-24.0-rc3",
            "OTP-24.0-rc2",
            "OTP-24.0-rc1",
            "OTP-23.0-rc3",
            "OTP-23.0-rc2",
            "OTP-23.0-rc1",
            "OTP-20.0",
            "OTP-22.0-rc3",
            "OTP-22.0-rc2",
            "OTP-22.0-rc1",
            "OTP-19.0",
            "OTP-21.0-rc2",
            "OTP-18.0",
            "OTP-21.0-rc1",
            "OTP-17.0",
            "OTP-20.0-rc2",
            "OTP-20.0-rc1",
            "OTP-19.0-rc2",
            "OTP-19.0-rc1",
            "OTP-18.0-rc1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-71562.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.277117023Z",
      "provider": "osv",
      "references": [
        "https://cna.erlef.org/cves/CVE-2026-71562.html",
        "https://github.com",
        "https://osv.dev/vulnerability/EEF-CVE-2026-71562",
        "https://www.erlang.org/doc/system/versions.html#order-of-versions",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71562.json",
        "https://github.com/erlang/otp/security/advisories/GHSA-cqx9-9hq6-m8wf",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-71562",
        "https://github.com/erlang/otp/commit/aba0fe8c2d700bf4ac94607cf7f00e53bbe4042d",
        "https://github.com/erlang/otp/commit/e3be1cfe9f6cedd0cd20d9905e05601dfb31c8aa",
        "https://github.com/erlang/otp"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1284"
        ],
        "cna_assigner": "EEF",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "5.10"
                  },
                  {
                    "fixed": "9.3.2.7"
                  },
                  {
                    "introduced": "9.4"
                  },
                  {
                    "fixed": "9.6.2.3"
                  },
                  {
                    "introduced": "9.7"
                  },
                  {
                    "fixed": "9.7.2"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71562.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-71562",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 491998,
  "published_at": "2026-09-01T14:33:41.833+00:00"
}