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High

Security advisory

Type: advisorySources: OSVCVE: CVE-2021-25829

An improper binary stream data handling issue was found in the [core] module of ONLYOFFICE DocumentServer v4.0.0-9-v5.6.3. Using this bug, an attacker is able to produce a denial of service attack that can eventually shut down the target server.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2021-25829
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 11:15 UTC · Revision 1

Source evidence

CVE-2021-25829

core-osv · Original source

Published 1 Mar 2021, 16:15 UTC

An improper binary stream data handling issue was found in the [core] module of ONLYOFFICE DocumentServer v4.0.0-9-v5.6.3. Using this bug, an attacker is able to produce a denial of service attack that can eventually shut down the target server.

osv:CVE-2021-25829
Complete source record
{
  "id": "0261e1087c6b43ac5bc30efa7578e057fed3a7921c8cad43a532a55868e8c545",
  "url": "https://osv.dev/vulnerability/CVE-2021-25829",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-25829",
    "summary": "An improper binary stream data handling issue was found in the [core] module of ONLYOFFICE DocumentServer v4.0.0-9-v5.6.3. Using this bug, an attacker is able to produce a denial of service attack that can eventually shut down the target server.",
    "evidence": "osv:CVE-2021-25829",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-25829",
      "aliases": [
        "CVE-2021-25829"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/onlyoffice/documentserver",
              "type": "GIT",
              "events": [
                {
                  "introduced": "1e2a61f6f4321e2571474068595dfe23a657cbdf"
                },
                {
                  "last_affected": "0187bea803abdd2b2b6ad8168272d77e27739add"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:onlyoffice:document_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "4.0.0-9"
                      },
                      {
                        "last_affected": "5.6.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "ONLYOFFICE-DocumentServer-5.6.3",
            "ONLYOFFICE-DocumentServer-5.6.2",
            "ONLYOFFICE-DocumentServer-5.6.1",
            "ONLYOFFICE-DocumentServer-5.6.0",
            "ONLYOFFICE-DocumentServer-5.5.3",
            "ONLYOFFICE-DocumentServer-5.5.1",
            "ONLYOFFICE-DocumentServer-5.5.0",
            "ONLYOFFICE-DocumentServer-5.4.2",
            "ONLYOFFICE-DocumentServer-5.4.1",
            "ONLYOFFICE-DocumentServer-5.4.0-2",
            "ONLYOFFICE-DocumentServer-5.3.4",
            "ONLYOFFICE-DocumentServer-5.3.2",
            "ONLYOFFICE-DocumentServer-5.3.1",
            "ONLYOFFICE-DocumentServer-5.3.0",
            "ONLYOFFICE-DocumentServer-5.2.8",
            "ONLYOFFICE-DocumentServer-5.2.7",
            "ONLYOFFICE-DocumentServer-5.2.6",
            "ONLYOFFICE-DocumentServer-5.2.4",
            "ONLYOFFICE-DocumentServer-5.2.3",
            "ONLYOFFICE-DocumentServer-5.2.2",
            "ONLYOFFICE-DocumentServer-5.2.0",
            "ONLYOFFICE-DocumentServer-5.1.5",
            "ONLYOFFICE-DocumentServer-5.1.4",
            "ONLYOFFICE-DocumentServer-5.1.3",
            "ONLYOFFICE-DocumentServer-5.1.2",
            "ONLYOFFICE-DocumentServer-5.1.1",
            "ONLYOFFICE-DocumentServer-5.1.0",
            "ONLYOFFICE-DocumentServer-5.0.7",
            "ONLYOFFICE-DocumentServer-5.0.6",
            "ONLYOFFICE-DocumentServer-5.0.5",
            "ONLYOFFICE-DocumentServer-5.0.4",
            "ONLYOFFICE-DocumentServer-5.0.3",
            "ONLYOFFICE-DocumentServer-4.4.3",
            "ONLYOFFICE-DocumentServer-4.4.2",
            "ONLYOFFICE-DocumentServer-4.4.1",
            "ONLYOFFICE-DocumentServer-4.3.6",
            "ONLYOFFICE-DocumentServer-4.3.5",
            "ONLYOFFICE-DocumentServer-4.3.4",
            "ONLYOFFICE-DocumentServer-4.3.3",
            "ONLYOFFICE-DocumentServer-4.3.2",
            "ONLYOFFICE-DocumentServer-4.3.1",
            "ONLYOFFICE-DocumentServer-4.3.0",
            "ONLYOFFICE-DocumentServer-4.2.11",
            "ONLYOFFICE-DocumentServer-4.2.10",
            "ONLYOFFICE-DocumentServer-4.2.9",
            "ONLYOFFICE-DocumentServer-4.0.0-9",
            "ONLYOFFICE-DocumentServer-4.2.8",
            "ONLYOFFICE-DocumentServer-4.2.7",
            "ONLYOFFICE-DocumentServer-4.2.5",
            "ONLYOFFICE-DocumentServer-4.2.4",
            "ONLYOFFICE-DocumentServer-4.2.3",
            "ONLYOFFICE-DocumentServer-4.2.1",
            "ONLYOFFICE-DocumentServer-4.2.0",
            "ONLYOFFICE-DocumentServer-4.1.8-1",
            "ONLYOFFICE-DocumentServer-4.1.6-3",
            "ONLYOFFICE-DocumentServer-4.1.5-1",
            "ONLYOFFICE-DocumentServer-4.1.4-3",
            "ONLYOFFICE-DocumentServer-4.1.2-37",
            "ONLYOFFICE-DocumentServer-4.0.3-3",
            "ONLYOFFICE-DocumentServer-4.0.2-4",
            "ONLYOFFICE-DocumentServer-4.0.1-34"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-25829.json"
          }
        }
      ],
      "modified": "2026-10-20T10:53:39.786851507Z",
      "provider": "osv",
      "references": [
        "https://github.com/ONLYOFFICE/core/blob/c1e4a2ce33bdcfab29d670f5fdb10fc63cf5fd6a/ASCOfficePPTXFile/PPTXFormat/Comments.h#L299",
        "https://github.com/ONLYOFFICE/core/blob/c1e4a2ce33bdcfab29d670f5fdb10fc63cf5fd6a/ASCOfficePPTXFile/PPTXFormat/Core.h#L161",
        "https://github.com/ONLYOFFICE/core/blob/c1e4a2ce33bdcfab29d670f5fdb10fc63cf5fd6a/ASCOfficePPTXFile/PPTXFormat/NotesMaster.h#L148",
        "https://github.com/ONLYOFFICE/core/blob/c1e4a2ce33bdcfab29d670f5fdb10fc63cf5fd6a/ASCOfficePPTXFile/PPTXFormat/NotesSlide.h#L141",
        "https://github.com/ONLYOFFICE/core/blob/c1e4a2ce33bdcfab29d670f5fdb10fc63cf5fd6a/ASCOfficePPTXFile/PPTXFormat/Presentation.h#L277",
        "https://github.com/ONLYOFFICE/core/blob/c1e4a2ce33bdcfab29d670f5fdb10fc63cf5fd6a/ASCOfficePPTXFile/PPTXFormat/Theme.h#L277",
        "https://github.com/ONLYOFFICE/core/blob/v5.6.4.10/ASCOfficePPTXFile/Editor/BinaryFileReaderWriter.cpp#L1722",
        "https://github.com/ONLYOFFICE/DocumentServer",
        "https://github.com/ONLYOFFICE/core",
        "https://github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25829"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-25829",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 384469,
  "published_at": "2021-03-01T16:15:14.15+00:00"
}