CVE-2021-22667Network attack vector

Unauthenticated code execution via hard-coded Telnet password

Published Feb 24, 2021 · Updated Aug 3, 2024

Hard-coded credentials in Advantech BB-ESWGP506-2SFP-T 1.01.01 and earlier allow remote attackers to execute arbitrary code via Telnet. The Telnet service listens on TCP port 23 by default and accepts a hard-coded password for the administrator account. No prior authentication is required; affected versions through 1.01.09 permit unauthorized administrator access, while code execution is documented through 1.01.01.

CVSS severity9.8
Critical
EPSS probability3.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Hard-coded credentials in Advantech BB-ESWGP506-2SFP-T 1.01.01 and earlier allow remote attackers to execute arbitrary code via Telnet. The Telnet service listens on TCP port 23 by default and accepts a hard-coded password for the administrator account. No prior authentication is required; affected versions through 1.01.09 permit unauthorized administrator access, while code execution is documented through 1.01.01.

The record

CVE
CVE-2021-22667
Published
Feb 24, 2021
Updated
Aug 3, 2024
Vendor
Advantech
Product
BB-ESWGP506-2SFP-T
Classifications
CWE-798, T1078.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 24, 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?

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

  1. Affected versionversion=Versions 1.01.09 and prior

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Advantech · BB-ESWGP506-2SFP-Tversion=Versions 1.01.09 and prior

Published CVSS scores

10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8Trend Micro Zero Day InitiativeCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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 exploitUnconfirmed

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials
T1078.001Valid Accounts: Default Accounts

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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