Umbraco Vulnerable to By-Pass of Configured Allowed Extensions for File Uploads

{
  "id": "fd624a2b056fb2960a728bfdf2d68da649ef23a884efc6142f7ee1b8bc79d190",
  "url": "https://osv.dev/vulnerability/CVE-2025-48953",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Umbraco Vulnerable to By-Pass of Configured Allowed Extensions for File Uploads",
    "summary": "Umbraco is an ASP.NET content management system (CMS). Starting in version 14.0.0 and prior to versions 15.4.2 and 16.0.0, it's possible to upload a file that doesn't adhere with the configured allowable file extensions via a manipulated API request. The issue is patched in versions 15.4.2 and 16.0.0. No known workarounds are available.",
    "evidence": "osv:CVE-2025-48953",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2025-48953",
      "aliases": [
        "CVE-2025-48953",
        "GHSA-fr6r-p8hv-x3c4"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/umbraco/umbraco-cms",
              "type": "GIT",
              "events": [
                {
                  "introduced": "8685c7d64a1c597983cfb82e1bd1d269d22e4508"
                },
                {
                  "fixed": "d920e93d1ee29dc3301697e444f53e8cd5db3cf9"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "14.0.0"
                      },
                      {
                        "fixed": "15.4.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "d920e93d1ee29dc3301697e444f53e8cd5db3cf9"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "cpe": "cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "14.0.0"
                      },
                      {
                        "fixed": "15.4.2"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-48953.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:53.320159265Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/48xxx/CVE-2025-48953.json",
        "https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-fr6r-p8hv-x3c4",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-48953",
        "https://github.com/umbraco/Umbraco-CMS/commit/d920e93d1ee29dc3301697e444f53e8cd5db3cf9"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-434"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/48xxx/CVE-2025-48953.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-48953",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 522144,
  "published_at": "2025-06-03T18:19:28.771+00:00"
}