CVE-2021-34795: Cisco Catalyst PON Series Switches Optical Network Terminal Vulnerabilities

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-11-04 · updated 2026-06-17
Weakness: CWE-284

Description

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.

Affected products

Cisco Catalyst Pon Switch Cgp-Ont-1P Firmware: before 1.1.1.14 — fixed in 1.1.1.14
Cisco Catalyst Pon Switch Cgp-Ont-4P Firmware: before 1.1.3.17 — fixed in 1.1.3.17
Cisco Catalyst Pon Switch Cgp-Ont-4Pv Firmware: before 1.1.3.17 — fixed in 1.1.3.17
Cisco Catalyst Pon Switch Cgp-Ont-4Pvc Firmware: before 1.1.3.17 — fixed in 1.1.3.17
Cisco Catalyst Pon Switch Cgp-Ont-4Tvcw Firmware: before 1.1.3.17 — fixed in 1.1.3.17

How to fix

Upgrade to a fixed version: Cisco Catalyst Pon Switch Cgp-Ont-1P Firmware 1.1.1.14; Cisco Catalyst Pon Switch Cgp-Ont-4P Firmware 1.1.3.17; Cisco Catalyst Pon Switch Cgp-Ont-4Pv Firmware 1.1.3.17; Cisco Catalyst Pon Switch Cgp-Ont-4Pvc Firmware 1.1.3.17; Cisco Catalyst Pon Switch Cgp-Ont-4Tvcw Firmware 1.1.3.17. Check the vendor advisory for mitigations.

References

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