VULNERABILITY INTELLIGENCE

CVE-2021-25831

CVSS score9.8 CRITICAL

EPSS probability11.50%

CISA KEVNot currently listed

Published2021-03-01

Last modified2026-06-17

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.