CVE-2021-3199

critical

Description

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.

References

https://github.com/ONLYOFFICE/DocumentServer/blob/903fe5ab7a275bd69c3c3346af2d21cf87ebeabf/CHANGELOG.md#563

https://thehackernews.com/2026/10/flax-typhoon-exploits-five-flaws-as.html

https://www.bleepingcomputer.com/news/security/fbi-disrupts-chinese-hacking-tools-used-to-breach-critical-infrastructure/

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3199

https://github.com/nola-milkin/poc_exploits/blob/master/CVE-2021-3199/poc_uploadImageFile.py

https://github.com/moehw/poc_exploits/tree/master/CVE-2021-3199/poc_uploadImageFile.py

https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-26539

Details

Source: Mitre, NVD

Published: 2021-01-26

Updated: 2026-10-09

Known Exploited Vulnerability (KEV)

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

Severity: High

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

EPSS

EPSS: 0.14548

Detections

Analytics