CVE intelligence and bounded remediation

CVE-2020-3218 — Cisco Ios Xe security vulnerability

High CVSS 9

A vulnerability in the web UI of Cisco IOS XE Software could allow an authenticated, remote attacker with administrative privileges to execute arbitrary code with root privileges on the underlying Linux shell. The vulnerability is due to improper validation of user-supplied input. An attacker could exploit this vulnerability by first creating a malicious file on the affected device itself and then uploading a second malicious file to the device. A successful exploit could allow the attacker to execute arbitrary code with root privileges or bypass licensing requirements on the device.

Severity
High
CVSS
9 (2.0)
Published
2020-06-03
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-20

Affected products

  • cisco / ios_xe / 16.6.1
  • cisco / ios_xe / 16.6.2
  • cisco / ios_xe / 16.6.3
  • cisco / ios_xe / 16.6.4
  • cisco / ios_xe / 16.6.4a
  • cisco / ios_xe / 16.6.4s

Showing 6 representative product identities from 58 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Command, code, expression, and template injection

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Check exposure

  • Trace untrusted values to process execution, interpreters, evaluators, template engines, dynamic imports, and administrative scripting features.
  • Determine whether the affected path is reachable across each trust boundary and which service account or host privilege it inherits.
  • Review configuration for optional execution features, unsafe compatibility modes, and shell invocation.

Remediate safely

  • Replace string-built commands or evaluated code with fixed operations and structured argument APIs that do not invoke a shell.
  • Use strict allowlists for operation identifiers and reject unexpected input before it reaches any interpreter.
  • Update the affected component and add inert regression tests covering metacharacters, encoding variants, and alternate request paths.

Authoritative sources

Complete CVE record and remediation plan

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