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Vulnerability DatabaseCVE-2021-25829

CVE-2021-25829: 
ONLYOFFICE DocumentServer vulnerability analysis and mitigation

Overview

CVE-2021-25829 is an improper binary stream data handling vulnerability discovered in the [core] module of ONLYOFFICE DocumentServer versions 4.0.0-9 through 5.6.3. The vulnerability was disclosed on March 1, 2021 (NVD).

Technical details

The vulnerability exists in the core module's binary stream data handling functionality. It has been assigned a CVSS v3.1 Base Score of 7.5 HIGH (Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and a CVSS v2.0 Base Score of 7.8 HIGH (Vector: AV:N/AC:L/Au:N/C:N/I:N/A:C) (NVD).

Impact

When exploited, this vulnerability allows an attacker to produce a denial of service attack that can eventually shut down the target server, disrupting the availability of ONLYOFFICE DocumentServer services (NVD).

Exploitability

The vulnerability can be exploited remotely without requiring authentication or user interaction. A proof-of-concept exploit has been published and is publicly available (POC Exploit).

Mitigation and workarounds

Users should upgrade to a version newer than ONLYOFFICE DocumentServer 5.6.3. The vulnerability has been fixed in subsequent releases (ONLYOFFICE Core).

Additional resources

Source: This report was generated using AI

Related ONLYOFFICE DocumentServer vulnerabilities:

CVE ID

Severity

Score

Technologies

Component name

CISA KEV exploit

Has fix

Published date

CVE-2023-46988MEDIUM6.7
  • ONLYOFFICE DocumentServer logoONLYOFFICE DocumentServer
  • cpe:2.3:a:onlyoffice:document_server
NoYesApr 01, 2025
CVE-2025-68917MEDIUM6.4
  • ONLYOFFICE DocumentServer logoONLYOFFICE DocumentServer
  • cpe:2.3:a:onlyoffice:document_server
NoYesDec 24, 2025
CVE-2025-68936MEDIUM6.1
  • ONLYOFFICE DocumentServer logoONLYOFFICE DocumentServer
  • cpe:2.3:a:onlyoffice:document_server
NoYesDec 25, 2025
CVE-2025-68935MEDIUM6.1
  • ONLYOFFICE DocumentServer logoONLYOFFICE DocumentServer
  • cpe:2.3:a:onlyoffice:document_server
NoYesDec 25, 2025
CVE-2023-50883MEDIUM6.1
  • ONLYOFFICE DocumentServer logoONLYOFFICE DocumentServer
  • cpe:2.3:a:onlyoffice:document_server
NoYesSep 09, 2024

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