Actively exploited in the wild
ONLYOFFICE Docs Server Path Traversal Vulnerability
ONLYOFFICE - Docs · Listed in the CISA KEV since 2026-10-08. This indicates confirmed attacks in production environments.
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CVE-2021-3199
CriticalCVSS 9.8KEVExploitation Probability (EPSS)
Very high risk97th percentile - higher than 97% of all known CVEs
Summary
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.
Risk Assessment
An attacker can remotely execute arbitrary code on the server, leading to full system compromise and access to processed documents.
Recommendation
Update ONLYOFFICE Document Server to version 5.6.3 or later and verify JWT configuration and path validation in file upload parameters.
Other vulnerabilities in ONLYOFFICE Document Server
See all- CVE-2026-110385High
A remote code execution vulnerability in ONLYOFFICE Document Server versions before 10.0.0 allows an authenticated attacker with a valid JWT to execute arbitrary operating system commands as the ds service account.
- CVE-2023-30188High
A memory exhaustion vulnerability in ONLYOFFICE Document Server versions 4.0.3 through 7.3.2 allows a remote attacker to cause a denial of service via a crafted JavaScript file.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS