CVE-2021-1451: Cisco IOS XE Software Easy Virtual Switching System Arbitrary Code Execution Vulnerability

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 3.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-03-24 · updated 2026-06-17
Weakness: CWE-119

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.

Affected products

Cisco IOS XE: 3.6.0be, 3.6.0e, 3.6.1e, 3.6.2e, 3.6.3e, 3.6.4e (+48)

References

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