CVE-2021-1577: Cisco Application Policy Infrastructure Controller

Critical severity, CVSS 9.1. EPSS: 1.3% chance of exploitation in the next 30 days.

A vulnerability in an API endpoint of Cisco Application Policy Infrastructure Controller (APIC) and Cisco Cloud Application Policy Infrastructure Controller (Cloud APIC) could allow an unauthenticated, remote attacker to read or write arbitrary files on an affected system. This vulnerability is due to improper access control. An attacker could exploit this vulnerability by using a specific API endpoint to upload a file to an affected device. A successful exploit could allow the attacker to read or write arbitrary files on an affected device.

Affected products

• Cisco Application Policy Infrastructure Controller: before 3.2\(10e\) (fixed in 3.2\(10e\)); from 4.0, before 4.2\(6h\) (fixed in 4.2\(6h\)); from 5.0, before 5.1\(3e\) (fixed in 5.1\(3e\))
• Cisco Cloud Application Policy Infrastructure Controller: before 3.2\(10e\) (fixed in 3.2\(10e\)); from 4.0, before 4.2\(6h\) (fixed in 4.2\(6h\)); from 5.0, before 5.1\(3e\) (fixed in 5.1\(3e\))

Published 2021-08-25. Last modified 2026-06-17.