CVE-2021-20637Network attack vector

WebUI denial of service via crafted URL

Published Feb 12, 2021 · Updated Aug 3, 2024

Improper exceptional-condition handling in Logitec LAN-W300N/PR5B allows remote attackers to interrupt its WebUI via a crafted URL. The flaw resides in WebUI request handling, but Logitec has not disclosed the exceptional condition or processing error that triggers it. Exploitation requires a user already logged into the administrative page to visit the crafted URL; the documented consequence is loss of WebUI access.

CVSS severity4.3
Medium
EPSS probability1.03%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper exceptional-condition handling in Logitec LAN-W300N/PR5B allows remote attackers to interrupt its WebUI via a crafted URL. The flaw resides in WebUI request handling, but Logitec has not disclosed the exceptional condition or processing error that triggers it. Exploitation requires a user already logged into the administrative page to visit the crafted URL; the documented consequence is loss of WebUI access.

The record

CVE
CVE-2021-20637
Published
Feb 12, 2021
Updated
Aug 3, 2024
Vendor
Logitec Corporation
Product
LAN-W300N/PR5B
Classifications
CWE-703, T1499
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=LAN-W300N/PR5B

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Logitec Corporation · LAN-W300N/PR5Bversion=LAN-W300N/PR5B

Published CVSS scores

2.6JPCERT/CC and IPAAV:N/AC:H/Au:N/C:N/I:N/A:P
4.3JPCERT/CC and IPACVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

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-703Improper Check or Handling of Exceptional Conditions
T1499Endpoint Denial of Service

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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