CVE-2021-3199
ONLYOFFICE Docs Server Path Traversal Vulnerability
ONLYOFFICE · Docs · Added to KEV: 2026-10-08 · Snapshot: 2026-10-18T20:43:22.315380+00:00
Technical context
Directory traversal with remote code execution can occur in /upload in ONLYOFFICE Document Server before 5.6.3, when JWT is used, via a /.. sequence in an image upload parameter.
Action and remediation
Review the vendor advisory, determine affected versions, apply the vendor-supported fix or mitigation, and validate the change.
Check vendor advisories and affected-version data before remediation. Validate affected software, identify internet reachability and business criticality in your authorised environment, and confirm mitigating controls. No AI-generated fix is asserted as vendor guidance.
Evidence links
Exposure and confidence limitations
Shodan identifies observable services but does not independently prove exploitation or confirm every affected software version. CyberIntel does not join this CVE to arbitrary public host IPs. No Tenable VPR or Qualys TruRisk score is calculated or implied.