CVE-2021-42851

Unauthenticated creation of standard user accounts

Published May 18, 2022 · Updated Aug 4, 2024

Missing authorization in Lenovo Personal Cloud Storage firmware allows remote attackers on an adjacent network to create standard user accounts. Lenovo has not disclosed the affected request handler or the authorization check omitted when account-creation input is processed. No authentication or user interaction is required, but the attacker must reach the appliance from an adjacent network; the created account has standard-user privileges.

CVSS severity6.3
Medium
EPSS probability0.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Lenovo Personal Cloud Storage firmware allows remote attackers on an adjacent network to create standard user accounts. Lenovo has not disclosed the affected request handler or the authorization check omitted when account-creation input is processed. No authentication or user interaction is required, but the attacker must reach the appliance from an adjacent network; the created account has standard-user privileges.

The record

CVE
CVE-2021-42851
Published
May 18, 2022
Updated
Aug 4, 2024
Vendor
Lenovo
Product
Personal Cloud Storage T2
Classifications
CWE-862, T1136.001
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 18, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <5.3.8.t2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Lenovo · Personal Cloud Storage T2version=unspecified <5.3.8.t2
Lenovo · Personal Cloud Storage A1version=unspecified <5.3.6.a1
Lenovo · Personal Cloud Storage T1version=unspecified <5.3.6.t1
Lenovo · Personal Cloud Storage X1version=unspecified <5.3.8.x1
Lenovo · Personal Cloud Storage T2Proversion=unspecified <5.3.7.t2-pro

Published CVSS scores

6.3LenovoCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
T1136.001Create Account: Local Account

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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