CVE-2021-1388: Cisco ACI Multi-Site Orchestrator

Critical severity, CVSS 10.0. EPSS: 14.8% chance of exploitation in the next 30 days.

A vulnerability in an API endpoint of Cisco ACI Multi-Site Orchestrator (MSO) installed on the Application Services Engine could allow an unauthenticated, remote attacker to bypass authentication on an affected device. The vulnerability is due to improper token validation on a specific API endpoint. An attacker could exploit this vulnerability by sending a crafted request to the affected API. A successful exploit could allow the attacker to receive a token with administrator-level privileges that could be used to authenticate to the API on affected MSO and managed Cisco Application Policy Infrastructure Controller (APIC) devices.

Affected products

• Cisco ACI Multi-Site Orchestrator: from 3.0, before 3.0\(3m\) (fixed in 3.0\(3m\))
• Cisco Application Policy Infrastructure Controller: version 3.0(3i) only

Published 2021-02-24. Last modified 2026-06-17.