No. CVE-2021-3199
A flaw in ONLYOFFICE Docs can let attackers take over the server
Being used now
Yes. Attackers are using this right now.
Organizations that host ONLYOFFICE Docs for shared editing.
What to do
Update ONLYOFFICE Docs to the latest version.
Confirmed in attacksOct 8, 2026
ProductONLYOFFICE Docs
Attack likelihood, next 30 days30%
Attack likelihood is EPSS, a daily estimate from FIRST.org of how likely this bug is to be used in attacks in the next 30 days.
The official description
ONLYOFFICE Docs contains a path traversal vulnerability that can occur when JWT is used, via a /.. sequence in an image upload parameter and could allow for remote code execution.
For your tech helper or AI assistant
A read-only checklist. Paste it into Claude, ChatGPT or a coding agent; it only looks and changes nothing.
Read-only check, change nothing, send nothing anywhere.
Is ONLYOFFICE Docs (CVE-2021-3199) installed or running on this machine or in this project?
1. Find every copy and its version (apps, packages, containers, lockfiles).
2. Compare each version against the vendor's fixed version for CVE-2021-3199. Quote the vendor page you used.
3. Report a table: where, version, fixed version, status (exposed / fixed / not installed / unsure).
4. List the exact update steps, but do not run them.