Cross Site Scripting Vulnerability in OnlyOffice by Ascensio System SIA
CVE-2025-10255

5.1MEDIUM

Key Information:

Vendor

Ascensio System Sia

Status
Onlyoffice
Vendor
CVE Published:
11 September 2025

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2025-10255?

A vulnerability has been identified in Ascensio System SIA's OnlyOffice, affecting versions up to 12.7.0. The flaw resides within the file /Products/Projects/Messages.aspx, specifically in the Comment Handler component. An attacker can exploit this vulnerability through remote manipulation, potentially leading to cross site scripting attacks. This exploit has been publicly disclosed, raising significant security concerns. Ascensio System SIA has acknowledged the issue and is actively working on a resolution that will be included in future patches.

Affected Version(s)

OnlyOffice 12.0

OnlyOffice 12.1

OnlyOffice 12.2

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2025-10255 - Proof of Concept

References

https://vuldb.com/?id.323615
vdb-entry
https://vuldb.com/?ctiid.323615
signaturepermissions-required
https://vuldb.com/?submit.635871
third-party-advisory

CVSS V4

Score:
5.1
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

0xHamy (VulDB User)
.