Puma PROXY Protocol v1 Accepts Repeated Protocol Headers on Persistent Connections

{
  "id": "60f3b35475eb049cefa3548457b86293df3ea086718ee012a7df44224966f20b",
  "url": "https://osv.dev/vulnerability/CVE-2026-47737",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Puma PROXY Protocol v1 Accepts Repeated Protocol Headers on Persistent Connections",
    "summary": "Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, Puma is vulnerable to source IP spoofing when set_remote_address proxy_protocol: :v1 is enabled and persistent connections are used because Puma incorrectly re-parses PROXY protocol headers after each keep-alive request on the same connection, allowing an attacker to inject a second PROXY header and overwrite REMOTE_ADDR. This issue is fixed in versions 7.2.1 and 8.0.2.",
    "evidence": "osv:CVE-2026-47737",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-47737",
      "aliases": [
        "CVE-2026-47737",
        "GHSA-2vqw-3mp8-cgmx"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/puma/puma",
              "type": "GIT",
              "events": [
                {
                  "introduced": "21e0443cca4a53c8f0f97fe5197423031cab3610"
                },
                {
                  "fixed": "92754ace040db67622f0e6406dea0b47c94d0139"
                },
                {
                  "introduced": "fcf3173a2eed8d350377891008a41630d976f3d9"
                },
                {
                  "fixed": "8085b75e79e3f7f1a96e5b488d74a71f62edd24d"
                },
                {
                  "fixed": "439c6136d9c2275721b7864db3ee78af7c80889f"
                },
                {
                  "fixed": "ebe9db3929ab8299d19c8f5b41e8ef4f4b22fa58"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "5.5.0"
                      },
                      {
                        "fixed": "7.2.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "8.0.0"
                      },
                      {
                        "fixed": "8.0.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "439c6136d9c2275721b7864db3ee78af7c80889f"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "ebe9db3929ab8299d19c8f5b41e8ef4f4b22fa58"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "92754ace040db67622f0e6406dea0b47c94d0139"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v7.2.1"
                  },
                  {
                    "range": [
                      {
                        "fixed": "8085b75e79e3f7f1a96e5b488d74a71f62edd24d"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v8.0.2"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v7.2.0",
            "v8.0.1",
            "v8.0.0",
            "v7.1.0",
            "v7.0.4",
            "v7.0.3",
            "v7.0.2",
            "v7.0.1",
            "v7.0.0",
            "v6.6.1",
            "v7.0.0.pre1",
            "v6.6.0",
            "v6.5.0",
            "v6.4.0",
            "v6.3.0",
            "v6.2.2",
            "v6.2.1",
            "v6.2.0",
            "v6.1.0",
            "v6.0.2",
            "v6.0.1",
            "v6.0.0",
            "v5.6.3",
            "v5.6.1",
            "v5.6.0",
            "v5.5.2",
            "v5.5.1",
            "v5.5.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-47737.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.858544970Z",
      "provider": "osv",
      "references": [
        "https://github.com/puma/puma/releases/tag/v7.2.1",
        "https://github.com/puma/puma/releases/tag/v8.0.2",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47737.json",
        "https://github.com/puma/puma/security/advisories/GHSA-2vqw-3mp8-cgmx",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-47737",
        "https://github.com/puma/puma/commit/439c6136d9c2275721b7864db3ee78af7c80889f",
        "https://github.com/puma/puma/commit/ebe9db3929ab8299d19c8f5b41e8ef4f4b22fa58",
        "https://github.com/puma/puma/pull/3944",
        "https://github.com/puma/puma/pull/3947"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-290",
          "CWE-345"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47737.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-47737",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 520304,
  "published_at": "2026-07-14T19:45:16.648+00:00"
}