CVE-2021-20647Network attack vector

Settings modification via forged administrator requests

Published Feb 12, 2021 · Updated Aug 3, 2024

Cross-site request forgery in ELECOM WRC-300FEBK-S allows remote attackers to alter router settings through an administrator's browser. A crafted page causes the logged-in browser to submit an arbitrary request to the web management interface; ELECOM has not disclosed the affected endpoint. Exploitation requires an administrator to remain logged in and visit the malicious page, after which settings can be changed or the telnet daemon started.

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-S allows remote attackers to alter router settings through an administrator's browser. A crafted page causes the logged-in browser to submit an arbitrary request to the web management interface; ELECOM has not disclosed the affected endpoint. Exploitation requires an administrator to remain logged in and visit the malicious page, after which settings can be changed or the telnet daemon started.

The record

CVE
CVE-2021-20647
Published
Feb 12, 2021
Updated
Aug 3, 2024
Vendor
ELECOM CO., LTD.
Product
WRC-300FEBK-S
Classifications
CWE-352, T1189
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-S

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ELECOM CO., LTD. · WRC-300FEBK-Sversion=WRC-300FEBK-S

Published CVSS scores

2.6JVNAV:N/AC:H/Au:N/C:N/I:P/A:N
4.3JVNCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/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)
T1189Drive-by Compromise

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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