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Vulnerability record · CVE-2021-25832 · published 1 March 2021

CVE-2021-25832: Onlyoffice document server out-of-bounds write vulnerability

Onlyoffice · Document Server

A heap buffer overflow vulnerability inside of BMP image processing was found at [core] module of ONLYOFFICE DocumentServer v4.0.0-9-v6.0.0. Using this vulnerability, an attacker is able to gain remote code executions on DocumentServer.

9.8 CVSS 3.1 Critical EPSS 13% · top 3.9% CWE-787 · Out-of-bounds write
9.8CVSS 3.1 base score, v2 7.5
13%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
14References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

A heap buffer overflow vulnerability inside of BMP image processing was found at [core] module of ONLYOFFICE DocumentServer v4.0.0-9-v6.0.0. Using this vulnerability, an attacker is able to gain remote code executions on DocumentServer.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/ONLYOFFICE/DocumentServer Product
https://github.com/ONLYOFFICE/core ProductVendor Advisory
https://github.com/ONLYOFFICE/core/blob/v6.0.1.15/ASCOfficePPTXFile/Editor/BinaryFileReaderWriter.cpp#L424 Vendor Advisory
https://github.com/ONLYOFFICE/core/blob/v6.0.1.15/ASCOfficePPTXFile/Editor/BinaryFileReaderWriter.cpp#L428 Vendor Advisory
https://github.com/ONLYOFFICE/core/blob/v6.0.1.15/DesktopEditor/cximage/CxImage/ximabmp.cpp#L354 Vendor Advisory
https://github.com/ONLYOFFICE/core/blob/v6.0.1.15/DesktopEditor/cximage/CxImage/ximabmp.cpp#L358 Vendor Advisory
https://github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25832 ExploitThird Party Advisory
https://github.com/ONLYOFFICE/DocumentServer Product
https://github.com/ONLYOFFICE/core ProductVendor Advisory
https://github.com/ONLYOFFICE/core/blob/v6.0.1.15/ASCOfficePPTXFile/Editor/BinaryFileReaderWriter.cpp#L424 Vendor Advisory
https://github.com/ONLYOFFICE/core/blob/v6.0.1.15/ASCOfficePPTXFile/Editor/BinaryFileReaderWriter.cpp#L428 Vendor Advisory
https://github.com/ONLYOFFICE/core/blob/v6.0.1.15/DesktopEditor/cximage/CxImage/ximabmp.cpp#L354 Vendor Advisory
https://github.com/ONLYOFFICE/core/blob/v6.0.1.15/DesktopEditor/cximage/CxImage/ximabmp.cpp#L358 Vendor Advisory
https://github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25832 ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2023-30186Onlyoffice document server use after free vulnerabilityA use after free issue discovered in ONLYOFFICE DocumentServer 4.0.3 through 7.3.2 allows remote attackers to run arbitrary code via crafted JavaScri…EPSS 2.3%9.8CVE-2023-30187Onlyoffice document server out-of-bounds write vulnerabilityAn out of bounds memory access vulnerability in ONLYOFFICE DocumentServer 4.0.3 through 7.3.2 allows remote attackers to run arbitrary code via craft…EPSS 2.4%9.8CVE-2022-29776Onlyoffice core out-of-bounds write vulnerabilityOnlyoffice Document Server v6.0.0 and below and Core 6.1.0.26 and below were discovered to contain a stack overflow via the component DesktopEditor/c…EPSS 6.9%9.8CVE-2022-29777Onlyoffice core out-of-bounds write vulnerabilityOnlyoffice Document Server v6.0.0 and below and Core 6.1.0.26 and below were discovered to contain a heap overflow via the component DesktopEditor/fo…EPSS 6.9%9.8CVE-2021-25830Onlyoffice document server vulnerabilityA file extension handling issue was found in [core] module of ONLYOFFICE DocumentServer v4.2.0.236-v5.6.4.13. An attacker must request the conversion…EPSS 12%9.8CVE-2021-25831Onlyoffice document server vulnerabilityA file extension handling issue was found in [core] module of ONLYOFFICE DocumentServer v4.0.0-9-v5.6.3. An attacker must request the conversion of t…EPSS 12%9.8CVE-2021-25833Onlyoffice document server path traversal vulnerabilityA 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…EPSS 44%9.8CVE-2021-3199Onlyoffice document server path traversal vulnerabilityDirectory traversal with remote code execution can occur in /upload in ONLYOFFICE Document Server before 5.6.3, when JWT is used, via a /.. sequence …EPSS 8.2%

Source: NIST National Vulnerability Database (record CVE-2021-25832), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.