CVE-2021-1388: Cisco ACI Multi-Site Orchestrator Application Services Engine Deployment Authentication Bypass Vulnerability

Severity: critical (CVSS 10.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 14.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-02-24 · updated 2026-06-17
Weakness: CWE-269

Description

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 Software: from 3.0 before 3.0\(3m\) — fixed in 3.0\(3m\)
Cisco Application Policy Infrastructure Controller (APIC): 3.0(3i)

How to fix

Upgrade to a fixed version: Cisco ACI Multi-Site Orchestrator Software 3.0\(3m\). Check the vendor advisory for mitigations.

References

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