CVE-2021-20646Network attack vector

Settings alteration via forged administrator-session requests

Published Feb 12, 2021 · Updated Aug 3, 2024

Cross-site request forgery in ELECOM WRC-300FEBK-A allows remote attackers to alter router settings or start its telnet daemon. The web setup interface accepts arbitrary state-changing requests from a malicious page under an administrator's existing authenticated session. An administrator must remain logged in and view the attacker-controlled page; published sources identify no specific endpoint or request-validation failure.

CVSS severity4.3
Medium
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site request forgery in ELECOM WRC-300FEBK-A allows remote attackers to alter router settings or start its telnet daemon. The web setup interface accepts arbitrary state-changing requests from a malicious page under an administrator's existing authenticated session. An administrator must remain logged in and view the attacker-controlled page; published sources identify no specific endpoint or request-validation failure.

The record

CVE
CVE-2021-20646
Published
Feb 12, 2021
Updated
Aug 3, 2024
Vendor
ELECOM CO., LTD.
Product
WRC-300FEBK-A
Classifications
CWE-352, CAPEC-62, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 12, 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=WRC-300FEBK-A

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ELECOM CO., LTD. · WRC-300FEBK-Aversion=WRC-300FEBK-A

Published CVSS scores

4.3JPCERT/CCCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
2.6JPCERT/CCAV:N/AC:H/Au:N/C:N/I:P/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery (CSRF)
CAPEC-62Cross Site Request Forgery
T1204.001User Execution: Malicious Link

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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