CVE-2021-34726: Cisco SD-WAN Software Command Injection Vulnerability

Severity: medium (CVSS 6.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-09-23 · updated 2026-06-17
Weakness: CWE-77

Description

A vulnerability in the CLI of Cisco SD-WAN Software could allow an authenticated, local attacker to inject arbitrary commands to be executed with root-level privileges on the underlying operating system of an affected device. This vulnerability is due to insufficient input validation on certain CLI commands. An attacker could exploit this vulnerability by authenticating to an affected device and submitting crafted input to the CLI. The attacker must be authenticated as an administrative user to execute the affected commands. A successful exploit could allow the attacker to execute commands with root-level privileges.

Affected products

Cisco Sd-Wan: before 18.4.6; from 19.2.0 before 19.2.3; from 20.1 before 20.1.2; from 20.3 before 20.3.1; from 20.4 before 20.4.1; from 20.5 before 20.5.1 — fixed in 18.4.6, 19.2.3, 20.1.2, 20.3.1, 20.4.1, 20.5.1

How to fix

Upgrade to a fixed version: Cisco Sd-Wan 18.4.6, 19.2.3, 20.1.2, 20.3.1. Check the vendor advisory for mitigations.

References

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