CVE-2026-20321: Cisco Application Policy Infrastructure Controller Apic

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

A vulnerability in the web-based management API for Cisco Application Policy Infrastructure Controller (APIC) could allow an authenticated, remote attacker to execute arbitrary commands as the root user. To exploit this vulnerability, the attacker must have valid administrative credentials. This vulnerability is due to insufficient input validation of user-controlled command arguments. An attacker could exploit this vulnerability by authenticating using the API and sending crafted input. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system of an affected device with root-level privileges.

Affected products

• Cisco Cisco Application Policy Infrastructure Controller Apic: version 5.3(1d) only; version 5.3(2a) only; version 5.3(2b) only; version 5.3(2c) only; version 5.3(2d) only; version 5.3(2e) only; …

Published 2026-10-07. Last modified 2026-10-08.