CVE-2021-43448Public exploitNetwork attack vector

User impersonation via unchecked WebSocket auth name

Published Jan 23, 2023 · Updated Apr 2, 2025

Improper input validation in ONLYOFFICE Document Server 7.0.0.49 and earlier allows remote attackers to impersonate document users. The WebSocket handler accepts the name supplied in the initial auth message and attributes later chat and document actions to that unchecked value. A document identifier is required, and another user must view the forged activity for the false identity to mislead collaborators.

CVSS severity5.3
Medium
EPSS probability1.01%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in ONLYOFFICE Document Server 7.0.0.49 and earlier allows remote attackers to impersonate document users. The WebSocket handler accepts the name supplied in the initial auth message and attributes later chat and document actions to that unchecked value. A document identifier is required, and another user must view the forged activity for the false identity to mislead collaborators.

The record

CVE
CVE-2021-43448
Published
Jan 23, 2023
Updated
Apr 2, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-20, T1036
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 23, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 2, 2025Record 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

5.3CISA-ADPCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
5.3NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N

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-20Improper Input Validation
T1036Masquerading

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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