CVE-2021-3199
Published · Updated
Prioritize patching. It under exploitation confirmed by CISA.
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.
ONLYOFFICE Document Server versions before 5.6.3 have a critical flaw in the upload feature that allows attackers to bypass folder restrictions using path traversal (/../ sequences) and upload malicious files that execute code on the server.
A directory traversal vulnerability in the /upload endpoint of ONLYOFFICE Document Server <5.6.3 allows unauthenticated or authenticated attackers to escape intended directory restrictions via ../ sequences in image upload parameters when JWT authentication is enabled, enabling arbitrary file upload and remote code execution on the server.