RCE in Ascensio System Sia Onlyoffice
CVE-2025-10255
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."
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.5 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (23.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000
Affected products
- Ascensio System Sia Onlyoffice — versions 12.0, 12.1, 12.2
Weakness classification (CWE)
Public proof-of-concept exploits
References
- vuldb.com/ (vdb-entry)
- vuldb.com/ (signature, permissions-required)
- vuldb.com/ (third-party-advisory)
- hkohi.ca/vulnerability/21 (exploit)
Frequently asked questions
- What is CVE-2025-10255?
- CVE-2025-10255 is a low-severity vulnerability in Ascensio System Sia Onlyoffice, classified under Cross-site Scripting. CVSS score: 3.5/10. Published 2025-09-11.
- How severe is CVE-2025-10255?
- Low severity. CVSS v3 base score is 3.5 out of 10.
- Is CVE-2025-10255 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.