CVE-2021-25830

moderate-risk

Published 2021-03-01

A 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 of the crafted file from DOCT into DOCX format. Using the chain of two other bugs related to improper string handling, an attacker can achieve remote code execution on DocumentServer.

Do I need to act?

6.1% chance of exploitation in next 30 days

EPSS score — moderate exploit probability

Not on CISA KEV list

No confirmed active exploitation reported to CISA

Patch status unknown

Check vendor advisories for fix availability and mitigation guidance

CVSS 9.8/10 Critical

NETWORK / LOW complexity

Affected Products (1)

Document Server

Affected Vendors

Onlyoffice

References (12)

Product https://github.com/ONLYOFFICE/DocumentServer

Product https://github.com/ONLYOFFICE/core

Third Party Advisory https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/Binar...

Third Party Advisory https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/PPTXFormat/L...

Exploit https://github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25830

Product https://github.com/ONLYOFFICE/DocumentServer

Product https://github.com/ONLYOFFICE/core

Third Party Advisory https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/Binar...

Third Party Advisory https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/PPTXFormat/L...

Exploit https://github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25830

/ 100

moderate-risk

Severity 32/34 · Critical

Exploitability 9/34 · Low

Exposure 5/34 · Minimal