CVE-2021-3199: onlyoffice document_server

CVSS 9.8 (critical) · listed as exploited by CISA since 2026-10-08 · published 2021-01-26

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.

Affected products (NVD): onlyoffice document_server

Fixed in (NVD): 5.6.3

Weakness: CWE-22

Source: NVD CVE-2021-3199

References

• https://github.com/ONLYOFFICE/DocumentServer/blob/903fe5ab7a275bd69c3c3346af2d21cf87ebeabf/CHANGELOG.md#563
• https://github.com/moehw/poc_exploits/tree/master/CVE-2021-3199/poc_uploadImageFile.py
• https://github.com/nola-milkin/poc_exploits/blob/master/CVE-2021-3199/poc_uploadImageFile.py
• https://github.com/ONLYOFFICE/DocumentServer/blob/903fe5ab7a275bd69c3c3346af2d21cf87ebeabf/CHANGELOG.md#563
• https://github.com/moehw/poc_exploits/tree/master/CVE-2021-3199/poc_uploadImageFile.py
• https://github.com/nola-milkin/poc_exploits/blob/master/CVE-2021-3199/poc_uploadImageFile.py
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3199

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