CVEvulnerability
CVE-2021-25831
9.8 CRITICAL
Official page ↗
- Status
- Modified
- Published
- 2021-03-01
- Last modified
- 2026-06-17
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CVSS 2.0 ([email protected])
- 7.5 HIGH — AV:N/AC:L/Au:N/C:P/I:P/A:P
Description
A 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 the crafted file from PPTT into PPTX format. Using the chain of two other bugs related to improper string handling, a remote attacker can obtain remote code execution on DocumentServer.
Affected configurations
• onlyoffice document server (>= 4.0.0-9 <= 5.6.3)
References
- https://github.com/ONLYOFFICE/DocumentServer Product
- https://github.com/ONLYOFFICE/core Product, Vendor Advisory
- https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/BinaryFileReaderWriter.cpp#L1918 Vendor Advisory
- https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/BinaryFileReaderWriter.cpp#L241 Vendor Advisory
- https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/PPTXFormat/Logic/Fills/BlipFill.cpp#L328 Vendor Advisory
- https://github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25831 Exploit, Vendor Advisory
- https://github.com/ONLYOFFICE/DocumentServer Product
- https://github.com/ONLYOFFICE/core Product, Vendor Advisory
- https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/BinaryFileReaderWriter.cpp#L1918 Vendor Advisory
- https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/BinaryFileReaderWriter.cpp#L241 Vendor Advisory
- https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/PPTXFormat/Logic/Fills/BlipFill.cpp#L328 Vendor Advisory
- https://github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25831 Exploit, Vendor Advisory