HOMEVULNERABILITIESCVE-2021-34795
CRITICAL

CVE-2021-34795

CWE-284Published: November 4, 2021· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-34795 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Cisco10 product(s)
catalyst pon switch cgp-ont-1p firmwarecatalyst pon switch cgp-ont-1pcatalyst pon switch cgp-ont-4p firmwarecatalyst pon switch cgp-ont-4pcatalyst pon switch cgp-ont-4pvc firmwarecatalyst pon switch cgp-ont-4pvccatalyst pon switch cgp-ont-4tvcw firmwarecatalyst pon switch cgp-ont-4tvcwcatalyst pon switch cgp-ont-4pv firmwarecatalyst pon switch cgp-ont-4pv
Source: NVD CPE · 10 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
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Official Patches & Advisories

All References (2)

Quick Facts

CVE IDCVE-2021-34795
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-284
CISA KEVNo
Affected1 vendor(s)
PublishedNov 4, 2021

Related CVEs (CWE-284)

Recommended Actions

  • Apply vendor patches immediately
  • Monitor CVE-2021-34795 in threat intel feeds
  • Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.