ONLYOFFICE Docs Image Upload Path Traversal via /../ Sequences Bypasses JWT and Enables Unauthenticated Remote Code Execution, Now Under an October 11th CISA KEV Federal Deadline

Last refreshed2026-10-09

Status: KEV | Advisory ID: CVE-2021-3199

Key Details

CVE	CVE-2021-3199
Vulnerability Name	ONLYOFFICE Docs Server Path Traversal Vulnerability
CVSS Score / Version	9.8 (Critical) / CVSS v3.1
Updated	2026-10-09
CVSS Vector	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
CVSS Prose	attack vector is network; attack complexity is low; privileges required is none; user interaction is none; scope is unchanged; confidentiality impact is high; integrity impact is high; availability impact is high.
Affected products	ONLYOFFICE Docs and ONLYOFFICE document_server
Exploitation status	Listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, indicating confirmed active exploitation.
Classified as	CWE-22 (Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'))
KEV listing	Added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-10-08.
Exploitation prediction (EPSS)	14.55% probability of exploitation in the next 30 days (97% percentile) -- FIRST.org's EPSS model.
Federal remediation deadline	2026-10-11 (CISA KEV, Binding Operational Directive).

Affected Products, Subsystems & Sectors

Vendor	Product	Affected Versions	Patch Status
ONLYOFFICE	Docs
ONLYOFFICE	document_server

Vendor

Product

Affected Versions

Patch Status

ONLYOFFICE

Docs

ONLYOFFICE

document_server

Subsystems	General OT
Sectors	Multiple

What to Know

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. (CISA)

What to Do

Monitor ONLYOFFICE's web page for any future patch releases.

References

Source	Reference
NVD	https://nvd.nist.gov/vuln/detail/CVE-2021-3199
CVE	https://www.cve.org/CVERecord?id=CVE-2021-3199

Source

Reference

NVD

https://nvd.nist.gov/vuln/detail/CVE-2021-3199

CVE

https://www.cve.org/CVERecord?id=CVE-2021-3199

KEV Required Action

Field	Value
KEV Link	https://www.cisa.gov/known-exploited-vulnerabilities-catalog
Date Added to KEV	2026-10-08
Required Action Due Date	2026-10-11
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.

Field

Value

KEV Link

https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Date Added to KEV

2026-10-08

Required Action Due Date

2026-10-11

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.