{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "cpe": "cpe:2.3:a:onlyoffice:document_server:*:*:*:*:*:*:*:*",
                "range": [
                  {
                    "introduced": "4.2.0.71"
                  },
                  {
                    "last_affected": "5.6.0.21"
                  }
                ],
                "source": "CPE_RANGE"
              }
            ]
          },
          "events": [
            {
              "introduced": "761b989ff2a0b022ea2526bbd798d285150c3c54"
            },
            {
              "last_affected": "ec87c3fd5e9ed78e1711d473c9f7052883fd6f5b"
            }
          ],
          "repo": "https://github.com/onlyoffice/server",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {},
  "details": "A file extension handling issue was found in [server] module of ONLYOFFICE DocumentServer v4.2.0.71-v5.6.0.21. The file extension is controlled by an attacker through the request data and leads to arbitrary file overwriting. Using this vulnerability, a remote attacker can obtain remote code execution on DocumentServer.",
  "id": "CVE-2021-25833",
  "modified": "2026-10-24T02:30:57.030474343Z",
  "published": "2021-03-01T16:15:14.510Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/ONLYOFFICE/server/blob/v5.6.0.21/DocService/sources/converterservice.js#L200"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/ONLYOFFICE/server/blob/v5.6.0.21/FileConverter/sources/converter.js#L283"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/ONLYOFFICE/server/blob/v5.6.0.21/FileConverter/sources/converter.js#L593"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/ONLYOFFICE/DocumentServer"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/ONLYOFFICE/server"
    },
    {
      "type": "EVIDENCE",
      "url": "https://github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25833"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}