CVE intelligence and bounded remediation

CVE-2021-1451 — Cisco Ios Xe security vulnerability

Critical CVSS 9.8

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.

Severity
Critical
CVSS
9.8 (3.1)
Published
2021-03-24
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-119

Affected products

  • cisco / ios_xe / 3.6.0be
  • cisco / ios_xe / 3.6.0e
  • cisco / ios_xe / 3.6.1e
  • cisco / ios_xe / 3.6.2e
  • cisco / ios_xe / 3.6.3e
  • cisco / ios_xe / 3.6.4e

Showing 6 representative product identities from 54 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Buffer bounds, memory safety, and memory corruption

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Check exposure

  • Identify affected native-code versions, build flags, architectures, parsers, codecs, drivers, and input paths in all shipped artifacts.
  • Determine whether untrusted data reaches the affected routine and the process privilege, sandbox, and network exposure.
  • Confirm statically linked, vendored, firmware, and platform-provided copies, not only package-manager records.

Remediate safely

  • Apply the maintained upstream correction or replace the affected component, then rebuild every dependent artifact from clean inputs.
  • Adopt bounds-checked interfaces, validated sizes and integer conversions, clear ownership, and memory-safe components where practical.
  • Enable supported compiler and runtime hardening and add sanitized tests and fuzz regression seeds derived from non-weaponized fixtures.

Authoritative sources

Complete CVE record and remediation plan

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