Webmin HTTP header authentication bypass

{
  "id": "95f501e7bec4a24d03b5960ff0ac57feb137a725950b288c21cd776537e3679a",
  "url": "https://osv.dev/vulnerability/CVE-2026-56020",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Webmin HTTP header authentication bypass",
    "summary": "The Webmin HTTP server (miniserv.pl) allows unauthenticated attackers to impersonate any user with a configured SSL client certificate by sending a forged HTTP header. A remote attacker can spoof certificate DNs and authenticate as any user. Fixed in 2.202.",
    "evidence": "osv:CVE-2026-56020",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-56020",
      "aliases": [
        "CVE-2026-56020"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/webmin/webmin",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "25321b467b2945d14de06781f10a98ca381a1e23"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.202"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "25321b467b2945d14de06781f10a98ca381a1e23"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "2.202"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.202"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.201",
            "2.200",
            "2.111",
            "2.110",
            "2.105",
            "2.104",
            "2.103",
            "2.100",
            "2.021",
            "2.020",
            "2.013",
            "2.012",
            "2.011",
            "2.010",
            "2.003",
            "2.001",
            "2.000",
            "1.999",
            "1.998",
            "1.996",
            "1.995",
            "1.994",
            "1.993",
            "1.991",
            "1.990",
            "1.984",
            "1.983",
            "1.982",
            "1.980",
            "1.974",
            "1.973",
            "1.972",
            "1.970",
            "1.962",
            "1.960",
            "1.955",
            "1.954",
            "1.953",
            "1.951",
            "1.950",
            "1.941",
            "1.940",
            "1.930",
            "1.920",
            "1.910",
            "1.900",
            "1.890",
            "1.880",
            "1.870",
            "1.860",
            "1.850",
            "1.840",
            "1.831",
            "1.830",
            "1.820",
            "1.810",
            "1.801",
            "1.800",
            "1.790",
            "1.780",
            "1.770",
            "1.760",
            "1.750",
            "1.740",
            "1.730",
            "1.720",
            "1.710",
            "1.700"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-56020.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:26.877528431Z",
      "provider": "osv",
      "references": [
        "https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-169-02.json",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56020.json",
        "https://github.com/webmin/webmin/releases/tag/2.202",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-56020",
        "https://webmin.com/security/#webmin-prior-to-2202",
        "https://www.cve.org/CVERecord?id=CVE-2026-56020"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-290"
        ],
        "cna_assigner": "cisa-cg",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56020.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-56020",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 493394,
  "published_at": "2026-06-18T16:12:05.368+00:00"
}