Is CVE-2021-1451 actively exploited?

No active exploitation of CVE-2021-1451 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-1451 be exploited remotely?

Yes. CVE-2021-1451 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-1451?

CVE-2021-1451 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2021-1451

CWE-119Published: March 24, 2021· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

A vulnerability in the Easy Virtual Switching System (VSS) feature of Cisco IOS XE Software for Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches could allow an unauthenticated, remote attacker to execute arbitrary code on the underlying Linux operating system of an affected device. The vulnerability is due to incorrect boundary checks of certain values in Easy VSS protocol packets that are destined for an affected device. An attacker could exploit this vulnerability by sending crafted Easy VSS protocol packets to UDP port 5500 while the affected device is in a specific state. When the crafted packet is processed, a buffer overflow condition may occur. A successful exploit could allow the attacker to trigger a denial of service (DoS) condition or execute arbitrary code with root privileges on the underlying Linux operating system of the affected device.

NVD Source

Technical Analysis

CVE-2021-1451 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.

From a weakness classification perspective (CWE-119): Buffer overflow vulnerabilities can lead to arbitrary code execution or denial of service by corrupting adjacent memory.