CVE-2021-40112Network attack vector

Unauthenticated configuration modification via improper HTTPS validation

Published Nov 4, 2021 · Updated Nov 7, 2024

Improper input validation in Cisco Catalyst PON Series Switches ONT allows remote attackers to modify device configuration via HTTPS. The web management interface accepts crafted HTTPS request parameters without properly validating them before applying configuration changes. No authentication is required, but the interface accepts only local LAN connections by default unless Remote Web Management is enabled.

CVSS severity8.6
High
EPSS probability1.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Cisco Catalyst PON Series Switches ONT allows remote attackers to modify device configuration via HTTPS. The web management interface accepts crafted HTTPS request parameters without properly validating them before applying configuration changes. No authentication is required, but the interface accepts only local LAN connections by default unless Remote Web Management is enabled.

The record

CVE
CVE-2021-40112
Published
Nov 4, 2021
Updated
Nov 7, 2024
Vendor
ClamAV
Product
Cisco Catalyst PON Series Switches
Classifications
CWE-284
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 4, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 7, 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=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Catalyst PON Series Switchesversion=n/a

Published CVSS scores

10.0Cisco CNA RecordCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
8.6Cisco Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/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.

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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-284Improper Access Control

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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