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CVE-2020-3403: Cisco IOS XE Software Command Injection Vulnerability

• Severity: high (CVSS 7.8 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: 2020-09-24 · updated 2026-06-17
• Weakness: CWE-78

Description

A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local attacker to inject a command to the underlying operating system that will execute with root privileges upon the next reboot of the device. The authenticated user must have privileged EXEC permissions on the device. The vulnerability is due to insufficient protection of values passed to a script that executes during device startup. An attacker could exploit this vulnerability by writing values to a specific file. A successful exploit could allow the attacker to execute commands with root privileges each time the affected device is restarted.

Affected products

• Cisco IOS XE: 17.2.1

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-cmdinj-2MzhjM6K
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-cmdinj-2MzhjM6K

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