CVE-2021-25831

moderate-risk
Published 2021-03-01

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.

Do I need to act?

~
3.5% 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
9
CVSS 9.8/10 Critical
NETWORK / LOW complexity

Affected Products (1)

Affected Vendors

Onlyoffice

References (12)

Product https://github.com/ONLYOFFICE/DocumentServer
Product https://github.com/ONLYOFFICE/core
Vendor Advisory https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/Binar...
Vendor Advisory https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/Binar...
Vendor 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-2021-25831
Product https://github.com/ONLYOFFICE/DocumentServer
Product https://github.com/ONLYOFFICE/core
Vendor Advisory https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/Binar...
Vendor Advisory https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/Binar...
Vendor 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-2021-25831
44
/ 100
moderate-risk
Severity 32/34 · Critical
Exploitability 7/34 · Low
Exposure 5/34 · Minimal