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Vulnerability record · public intelligence
CVE-2021-40113
CRITICAL

Cisco Catalyst PON Series Switches Optical Network Terminal Vulnerabilities

Published Nov 4, 2021 · Updated Oct 23, 2026

Severity · CVSSCRITICAL · 10.0
Known exploitationNot listed
EPSS / likelihood4.63%
QFinch risk score20 / 100

Original summary

Normalized public record · Updated Oct 23, 2026

Cisco Catalyst PON Series Switches Optical Network Terminal Vulnerabilities

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

Multiple vulnerabilities in the web-based management interface of the Cisco Catalyst Passive Optical Network (PON) Series Switches Optical Network Terminal (ONT) could allow an unauthenticated, remote attacker to perform the following actions: Log in with a default credential if the Telnet protocol is enabled Perform command injection Modify the configuration For more information about these vulnerabilities, see the Details section of this advisory.

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

CVENVDEPSS
SSVC priority
MEDIUM
Confidence
20%
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. 20211103 Cisco Catalyst PON Series Switches Optical Network Terminal Vulnerabilities ↗

Record history

Published Nov 4, 2021 · Last refreshed Oct 23, 2026