sending old referer

{
  "id": "b0e8bfecc0c7654f6f79f16d4a61a87773f0e11ecb85ee0304a76bed9dae7516",
  "url": "https://osv.dev/vulnerability/CURL-CVE-2026-9546",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "sending old referer",
    "summary": "A vulnerability in libcurl caused the HTTP `Referer:` header to persist even when explicitly cleared. While the documentation states that passing NULL to `CURLOPT_REFERER` suppresses the header, the option failed to clear the internal state. As a result, the previous referrer string was erroneously reused and sent in subsequent requests, potentially leaking sensitive information to unintended servers.",
    "evidence": "osv:CURL-CVE-2026-9546",
    "products": [],
    "severity": "low",
    "structured": {
      "id": "CURL-CVE-2026-9546",
      "aliases": [
        "CURL-CVE-2026-9546",
        "CVE-2026-9546"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "8.18.0"
                },
                {
                  "fixed": "8.20.1"
                },
                {
                  "introduced": "8.21.0"
                },
                {
                  "fixed": "8.21.0"
                }
              ]
            },
            {
              "repo": "https://github.com/curl/curl.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "2cb868242dc2ac9cd52ee64987ef51d5964a56f9"
                },
                {
                  "fixed": "862e8a74a84478d82973471b4f49dc2746c1780e"
                }
              ]
            }
          ],
          "versions": [
            "8.20.0",
            "8.19.0",
            "8.18.0",
            "curl-8_20_0",
            "rc-8_20_0-3",
            "rc-8_20_0-2",
            "rc-8_20_0-1",
            "curl-8_19_0",
            "rc-8_19_0-3",
            "rc-8_19_0-2",
            "rc-8_19_0-1",
            "curl-8_18_0",
            "rc-8_18_0-3",
            "rc-8_18_0-2",
            "rc-8_18_0-1"
          ],
          "database_specific": {
            "source": "https://curl.se/docs/CURL-CVE-2026-9546.json",
            "vanir_signatures": [
              {
                "id": "CURL-CVE-2026-9546-7ba9ca43",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "329802710635362475633966257142929289229",
                    "59722172210655117825890418870938329781",
                    "183831522990858182837473479172905867047",
                    "304554302798540308152858876043779062238"
                  ]
                },
                "source": "https://github.com/curl/curl.git/commit/862e8a74a84478d82973471b4f49dc2746c1780e",
                "target": {
                  "file": "lib/transfer.c"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              },
              {
                "id": "CURL-CVE-2026-9546-93bc1aa3",
                "digest": {
                  "length": 3790,
                  "function_hash": "192731219037552860576466850254657292841"
                },
                "source": "https://github.com/curl/curl.git/commit/862e8a74a84478d82973471b4f49dc2746c1780e",
                "target": {
                  "file": "lib/transfer.c",
                  "function": "Curl_pretransfer"
                },
                "deprecated": false,
                "signature_type": "Function",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-25T01:05:12Z"
          }
        }
      ],
      "modified": "2026-10-25T01:05:12.983225194Z",
      "provider": "osv",
      "references": [],
      "provider_metadata": {
        "CWE": {
          "id": "CWE-200",
          "desc": "Exposure of Sensitive Information to an Unauthorized Actor"
        },
        "URL": "https://curl.se/docs/CVE-2026-9546.json",
        "www": "https://curl.se/docs/CVE-2026-9546.html",
        "issue": "https://hackerone.com/reports/3754343",
        "affects": "lib",
        "package": "curl",
        "severity": "Low",
        "last_affected": "8.20.0"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-9546",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 444356,
  "published_at": "2026-06-24T08:00:00+00:00"
}