CVE-2021-3199
KEVONLYOFFICE Docs Server Path Traversal Vulnerability
Description
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.
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.
CVSS 3.1 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HPublishedJan 26, 2021
Last modifiedOct 9, 2026
Added to KEVOct 8, 2026
Remediation dueOct 11, 2026
References
- github.com/ONLYOFFICE/DocumentServer/blob/903fe5ab7a275bd69c3c3346af2d21cf87ebeabf/CHANGELOG.mdRelease NotesThird Party Advisory
- github.com/moehw/poc_exploits/tree/master/CVE-2021-3199/poc_uploadImageFile.pyExploitThird Party Advisory
- github.com/nola-milkin/poc_exploits/blob/master/CVE-2021-3199/poc_uploadImageFile.pyExploitThird Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3199US Government Resource
0 recent articles mention this CVE
82
Risk assessment · Critical
Actively exploited. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 15 days
- CVSS
- 9.8 CRITICAL
- EPSS (30-day exploit probability)
- 30.2% · top 2% of all CVEs
- Weakness
- CWE-22
- Attack vector
- Network, remotely reachable
- Preconditions
- No privileges and no user interaction
Recommended actions
- 1.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.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.