9router: Unauthenticated `/v1` proxy access via `Host`-header spoofing → open AI relay + SSRF

{
  "id": "8ab6c113151a408fe0dc925f55e534e02d6c74fa38c11290bf6bd33de8487cca",
  "url": "https://osv.dev/vulnerability/CVE-2026-55641",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "9router: Unauthenticated `/v1` proxy access via `Host`-header spoofing → open AI relay + SSRF",
    "summary": "9Router is an AI router & token saver. Prior to 0.5.2, 9router determines whether a /v1 LLM proxy request is local by reading the client-controlled Host header, allowing a remote unauthenticated attacker to send Host: localhost and bypass API-key authentication. In the default configuration, this exposes the /v1 proxy to upstream provider calls using stored provider credentials and allows /v1/search with the searxng provider_options.baseUrl parameter to drive server-side requests to internal or cloud-metadata hosts. This issue is fixed in version 0.5.2.",
    "evidence": "osv:CVE-2026-55641",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-55641",
      "aliases": [
        "CVE-2026-55641",
        "GHSA-86m2-fcxq-5q7c"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/decolua/9router",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5da508af3c3dc6e920286141d1a4ddcd4ec245db"
                },
                {
                  "fixed": "b282f0554972ea35281520738759d76abcd0b0b3"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.5.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "b282f0554972ea35281520738759d76abcd0b0b3"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "5da508af3c3dc6e920286141d1a4ddcd4ec245db"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v0.5.2"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.4.80",
            "v0.4.71",
            "v0.4.66",
            "v0.4.63",
            "v0.4.62",
            "v0.4.59",
            "v0.4.58",
            "v0.4.55",
            "v0.4.52",
            "v0.4.50",
            "v0.4.49",
            "v0.4.46",
            "v0.4.44",
            "v0.4.41",
            "v0.4.39",
            "v0.4.38",
            "v0.4.37",
            "v0.4.36",
            "v0.4.33",
            "v0.4.31",
            "v0.4.30",
            "v0.4.29",
            "v0.4.28",
            "v0.4.27",
            "v0.4.25",
            "v0.4.20",
            "v0.4.19",
            "v0.4.18",
            "v0.4.16",
            "v0.4.14",
            "v0.4.13",
            "v0.4.12",
            "v0.4.11",
            "v0.4.10",
            "v0.4.8",
            "v0.4.6",
            "v0.4.4",
            "v0.4.3",
            "v0.4.2",
            "v0.4.1",
            "v0.3.98",
            "v0.3.97",
            "v0.3.91",
            "v0.3.90",
            "v0.3.89",
            "v0.3.87",
            "v0.3.86",
            "v0.3.83",
            "v0.3.75",
            "v0.3.47",
            "v0.3.42",
            "v0.3.34",
            "v0.3.17",
            "v0.2.89",
            "v0.2.79",
            "v0.2.71",
            "v0.2.70",
            "v0.2.67",
            "v0.2.56",
            "v0.2.52",
            "v0.2.43",
            "v0.2.36",
            "v0.2.31",
            "v0.2.27",
            "v0.2.21"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55641.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:28.761296537Z",
      "provider": "osv",
      "references": [
        "https://github.com/decolua/9router/releases/tag/v0.5.2",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55641.json",
        "https://github.com/decolua/9router/security/advisories/GHSA-86m2-fcxq-5q7c",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-55641",
        "https://github.com/decolua/9router/commit/b282f0554972ea35281520738759d76abcd0b0b3"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1327",
          "CWE-290",
          "CWE-348",
          "CWE-918"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55641.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-55641",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 495480,
  "published_at": "2026-07-10T15:36:05.964+00:00"
}