Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2021-3199

CVE-2021-3199CRITICAL

n/a n/a — Directory traversal with remote code execution can occur in /upload in ONLYOFFICE Document Server before 5.6.3, when JWT is used, via a /..

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  H  H  H    9.8   .2014   97.4   YES

AFFECTED
  Product  Versions  Fixed
  n/a      n/a –     —

TIMELINE
  Jan 21  Reserved by mitre
  Jan 22  Published (CNA: mitre)
  Oct 8   ADDED TO KEV — CVE-2021-3199. Remediation due October 11, 2026.
  Oct 9   EXPLOIT PUBLISHED — CVE-2021-3199. Public exploit reference added.
  Oct 12  DUE DATE PASSED — CVE-2021-3199. CISA remediation deadline was October 11, 2026; still in catalog.

CWE-22 · CNA: mitre · CVSS v3.1 · 4 references · NVD status: Analyzed · KEV due October 11, 2026

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.

Lifecycle

Complete event history — 5 events, chronological
Date	Event	Detail
January 21, 2021	Reserved	Reserved by mitre
January 22, 2021	Published	Published (CNA: mitre)
October 8, 2026	KEV ADDED	ADDED TO KEV — CVE-2021-3199. Remediation due October 11, 2026.
October 9, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2021-3199. Public exploit reference added.
October 12, 2026	DUE DATE PASSED	DUE DATE PASSED — CVE-2021-3199. CISA remediation deadline was October 11, 2026; still in catalog.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
n/a	n/a	—	n/a	—

Weaknesses

CWE-22

References (4)

https://github.com/ONLYOFFICE/DocumentServer/blob/903fe5ab7a275bd69c3c3346af2d21cf87ebeabf/CHANGELOG.md#563 [Release Notes, Third Party Advisory]
https://github.com/moehw/poc_exploits/tree/master/CVE-2021-3199/poc_uploadImageFile.py [Exploit, Third Party Advisory]
https://github.com/nola-milkin/poc_exploits/blob/master/CVE-2021-3199/poc_uploadImageFile.py [Exploit, Third Party Advisory]
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3199 [US Government Resource]

Authoritative record: CVE-2021-3199 at cve.org

Weaknesses: CWE-22

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-3199 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.