CVE-2025-10255: Ascensio System Sia ONLYOFFICE

Low severity, CVSS 3.5. EPSS: 0.3% chance of exploitation in the next 30 days.

A vulnerability was determined in Ascensio System SIA OnlyOffice up to 12.7.0. Impacted is an unknown function of the file /Products/Projects/Messages.aspx of the component Comment Handler. Executing manipulation can lead to cross site scripting. The attack may be launched remotely. The exploit has been publicly disclosed and may be utilized. The vendor was informed early about this issue and replied: "We are already working on this case, and the issues will be resolved in one of the upcoming patches."

Affected products

• Ascensio System Sia ONLYOFFICE: version 12.0 only; version 12.1 only; version 12.2 only; version 12.3 only; version 12.4 only; version 12.5 only; …

Published 2025-09-11. Last modified 2026-06-17.