CVE-2021-25833

moderate-risk

Published 2021-03-01

A 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 attacker through the request data and leads to arbitrary file overwriting. Using this vulnerability, a remote attacker can obtain remote code execution on DocumentServer.

Do I need to act?

9.6% 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/server

Third Party Advisory https://github.com/ONLYOFFICE/server/blob/v5.6.0.21/DocService/sources/converter...

Third Party Advisory https://github.com/ONLYOFFICE/server/blob/v5.6.0.21/FileConverter/sources/conver...

Exploit https://github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25833

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

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

Third Party Advisory https://github.com/ONLYOFFICE/server/blob/v5.6.0.21/DocService/sources/converter...

Third Party Advisory https://github.com/ONLYOFFICE/server/blob/v5.6.0.21/FileConverter/sources/conver...

Exploit https://github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25833

/ 100

moderate-risk

Severity 32/34 · Critical

Exploitability 11/34 · Low

Exposure 5/34 · Minimal