Cisco Application Policy Infrastructure Controller API Command Injection Vulnerability

Description

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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apic-cmdinj-L6VR4E7 This advisory is part of a group of advisories. For a complete list of the advisories and links to them, see Cisco Advance Notification for Publication of October 7, 2026, Security Advisories . For further documentation of improvements and fixes in Cisco APIC, see Cisco Application Policy Infrastructure Controller Security Hardening Release: October 2026 . Security Impact Rating: Medium CVE: CVE-2026-20321

What to do

Install the fixed versions listed in the official advisory. If you cannot update right away, apply the workarounds or mitigations it describes and limit access to the affected service.

Details

Vendor

Cisco

Product

Cisco APIC

CVE

CVE-2026-20321

Affected versions

Cisco Application Policy Infrastructure Controller (APIC) 5.3: 7 versions, from 5.3(1d) to 5.3(2f)
Cisco Application Policy Infrastructure Controller (APIC) 6.1: 6.1(5e)
Cisco Application Policy Infrastructure Controller (APIC) 6.2: 6.2(1f); 6.2(1g); 6.2(2e) (from the advisory and NVD; check the exact builds in the official advisory)

CVSS score

6.5

Actively exploited

Not known at this time

Source

Cisco PSIRT – original advisory

Published

October 7, 2026

The description and the recommended action are quoted from the public advisory (the action is our generic advice); severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.