CVE-2021-25833Public exploitNetwork attack vector

Unauthenticated code execution via arbitrary file overwrite

Published Mar 1, 2021 · Updated Aug 3, 2024

Path traversal in ONLYOFFICE DocumentServer 4.2.0.71 through 5.6.0.21 allows remote attackers to execute arbitrary code via request data. The conversion API copies the request's filetype value into cmd.getFormat(), which FileConverter appends to a temporary source pathname before writing downloaded bytes. No authentication or user interaction is required, and traversal in that extension can overwrite a server-side file to obtain code execution.

CVSS severity9.8
Critical
EPSS probability43.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in ONLYOFFICE DocumentServer 4.2.0.71 through 5.6.0.21 allows remote attackers to execute arbitrary code via request data. The conversion API copies the request's filetype value into cmd.getFormat(), which FileConverter appends to a temporary source pathname before writing downloaded bytes. No authentication or user interaction is required, and traversal in that extension can overwrite a server-side file to obtain code execution.

The record

CVE
CVE-2021-25833
Published
Mar 1, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-22, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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