← Vulnerability feed

Vulnerability record · CVE-2021-3199 · published 26 January 2021

CVE-2021-3199: Onlyoffice document server path traversal vulnerability

Onlyoffice · Document Server

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.

9.8 CVSS 3.1 Critical CISA KEV since 8 Oct 2026 EPSS 30% · top 1.8% CWE-22 · Path traversal
9.8CVSS 3.1 base score, v2 7.5
30%EPSS exploitation probability, 30 days
YesIn CISA KEV, fix deadline passed
1Affected product versions listed by NVD
7References, 4 tagged exploit
9 Oct 2026Last modified by NVD

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.

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

Exploitation in the wild

CISA added CVE-2021-3199 to the Known Exploited Vulnerabilities catalog on 8 October 2026 as "ONLYOFFICE Docs Server Path Traversal Vulnerability". Required action: 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. Federal deadline 11 October 2026.

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

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

Track CVE-2021-3199 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2023-30186Onlyoffice document server use after free vulnerabilityA use after free issue discovered in ONLYOFFICE DocumentServer 4.0.3 through 7.3.2 allows remote attackers to run arbitrary code via crafted JavaScri…EPSS 2.3%9.8CVE-2023-30187Onlyoffice document server out-of-bounds write vulnerabilityAn out of bounds memory access vulnerability in ONLYOFFICE DocumentServer 4.0.3 through 7.3.2 allows remote attackers to run arbitrary code via craft…EPSS 2.4%9.8CVE-2022-29776Onlyoffice core out-of-bounds write vulnerabilityOnlyoffice Document Server v6.0.0 and below and Core 6.1.0.26 and below were discovered to contain a stack overflow via the component DesktopEditor/c…EPSS 7.0%9.8CVE-2022-29777Onlyoffice core out-of-bounds write vulnerabilityOnlyoffice Document Server v6.0.0 and below and Core 6.1.0.26 and below were discovered to contain a heap overflow via the component DesktopEditor/fo…EPSS 7.0%9.8CVE-2021-25830Onlyoffice document server vulnerabilityA file extension handling issue was found in [core] module of ONLYOFFICE DocumentServer v4.2.0.236-v5.6.4.13. An attacker must request the conversion…EPSS 12%9.8CVE-2021-25833Onlyoffice document server path traversal vulnerabilityA file extension handling issue was found in [server] module of ONLYOFFICE DocumentServer v4.2.0.71-v5.6.0.21. The file extension is controlled by an…EPSS 44%9.8CVE-2021-25831Onlyoffice document server vulnerabilityA file extension handling issue was found in [core] module of ONLYOFFICE DocumentServer v4.0.0-9-v5.6.3. An attacker must request the conversion of t…EPSS 12%9.8CVE-2021-25832Onlyoffice document server out-of-bounds write vulnerabilityA heap buffer overflow vulnerability inside of BMP image processing was found at [core] module of ONLYOFFICE DocumentServer v4.0.0-9-v6.0.0. Using th…EPSS 13%

Source: NIST National Vulnerability Database (record CVE-2021-3199), CISA KEV, FIRST EPSS (scores of 2026-11-11). This page is refreshed as NVD updates the record.