Risk Letters

Exploited vulnerability

CVE-2021-3199

TLP:CLEAR

ONLYOFFICE Docs Server Path Traversal Vulnerability

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.

Facts

  • Vendor: ONLYOFFICE
  • Product: Docs
  • CVSS: 9.8
  • EPSS (probability of exploitation within 30 days): 30.2 %
  • On CISA's Known Exploited Vulnerabilities list since: 8 October 2026
  • First known exploitation: 8 October 2026
  • CISA's deadline for US federal agencies: 11 October 2026
  • Weakness: CWE-22
  • First seen by Risk Letters: 8 October 2026

Members see which Nordic sectors the flaw hits, and what to do about it.

Get the full brief

Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD