CVE-2021-40866Public exploitNetwork attack vector

Administrator takeover via omitted authentication TLV

Published Sep 13, 2021 · Updated Aug 4, 2024

Improper authentication in NETGEAR smart switch firmware allows remote attackers to change the administrator password via an NSDP packet. The /sqfs/bin/sccd daemon processes a type 9 password-change TLV without requiring a preceding successful type 10 authentication TLV. SCC Control must be manually enabled on the local network; exploitation resets the administrative credential and enables full device compromise.

CVSS severity9.8
Critical
EPSS probability1.76%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in NETGEAR smart switch firmware allows remote attackers to change the administrator password via an NSDP packet. The /sqfs/bin/sccd daemon processes a type 9 password-change TLV without requiring a preceding successful type 10 authentication TLV. SCC Control must be manually enabled on the local network; exploitation resets the administrative credential and enables full device compromise.

The record

CVE
CVE-2021-40866
Published
Sep 13, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-287, T1098
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 13, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.4NIST National Vulnerability DatabaseAV:A/AC:M/Au:N/C:P/I:P/A:P
9.8MITRECVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.8NIST National Vulnerability DatabaseCVSS:3.1/AV:A/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-287Improper Authentication
T1098Account Manipulation

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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