CVE-2021-45520

Unauthenticated device access via hardcoded password

Published Dec 26, 2021 · Updated Aug 4, 2024

Authentication bypass in NETGEAR RBK352, RBR350, and RBS350 firmware before 4.4.0.10 lets remote attackers access devices via adjacent networks. The affected firmware contains a hardcoded password that permits authentication without a device-specific secret, but public records do not identify the exact code path or interface. An attacker requires no prior account and local-network reachability; successful authentication can expose, alter, or disrupt router operation.

CVSS severity9.6
Critical
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in NETGEAR RBK352, RBR350, and RBS350 firmware before 4.4.0.10 lets remote attackers access devices via adjacent networks. The affected firmware contains a hardcoded password that permits authentication without a device-specific secret, but public records do not identify the exact code path or interface. An attacker requires no prior account and local-network reachability; successful authentication can expose, alter, or disrupt router operation.

The record

CVE
CVE-2021-45520
Published
Dec 26, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-798, T1078
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 26, 2021CVE 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.8NVDAV:A/AC:L/Au:N/C:P/I:P/A:P
9.6MITRE CNACVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials
T1078Valid Accounts

Public exploit references

No public exploit references are available in this record.

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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