CVE-2021-1594 Cisco Identity Services Engine Privilege Escalation Vulnerability
An attacker in a man-in-the-middle position can inject commands into Cisco ISE API endpoints to execute arbitrary code with root privileges.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2021-1594?
CVE-2021-1594 is a high-severity command injection vulnerability in Cisco Identity Services Engine, published on 6 Oct 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
A vulnerability in the REST API of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to perform a command injection attack and elevate privileges to root. This vulnerability is due to insufficient input validation for specific API endpoints. An attacker in a man-in-the-middle position could exploit this vulnerability by intercepting and modifying specific internode communications from one ISE persona to another ISE persona. A successful exploit could allow the attacker to run arbitrary commands with root privileges on the underlying operating system. To exploit this vulnerability, the attacker would need to decrypt HTTPS traffic between two ISE personas that are located on separate nodes.
Which versions are affected by CVE-2021-1594?
It affects 1 product.
Products include Cisco Identity Services Engine.
How do I fix CVE-2021-1594?
No fix has been published for CVE-2021-1594 yet. Limit exposure of the affected software until one is available.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2021-1594 being exploited?
There is no known exploitation of CVE-2021-1594 in the wild and no public exploit code.
Other vulnerabilities in Cisco Identity Services Engine
- CVE-2026-76460 Cisco Identity Services Engine Incorrect Use of Privileged APIs
- CVE-2025-20337 Cisco Identity Services Engine Injection
- CVE-2025-20281 Cisco Identity Services Engine Injection
- CVE-2026-20130 Cisco Identity Services Engine Hardening Release - Improper Neutralization Vulnerabilities
- CVE-2026-20192 Cisco Identity Services Engine Hardening Release - Access Control Vulnerabilities
Sources
Also known as GHSA-8rx9-j5hq-fx8v.