CVE-2026-20195 Cisco Identity Services Engine Observable Response Discrepancy Vulnerability

Medium 5.3 Published 6 May 2026 Updated 6 May 2026

Unauthenticated attackers can enumerate valid user accounts by analyzing error messages from the identity management API endpoint.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-20195?

CVE-2026-20195 is a medium-severity vulnerability in Cisco Identity Services Engine, published on 6 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A vulnerability in an identity management API endpoint of Cisco ISE could allow an unauthenticated, remote attacker to enumerate valid user accounts on an affected device. This vulnerability exists because error messages are observed when the affected API endpoint is called. An attacker could exploit this vulnerability by sending a series of crafted requests to the affected endpoint and analyzing the differentiated responses. A successful exploit could allow the attacker to compile a list of valid usernames on an affected system.

Weakness: CWE-204

Which versions are affected by CVE-2026-20195?

It affects 1 product.

Products include Cisco Identity Services Engine.

How do I fix CVE-2026-20195?

No fix has been published for CVE-2026-20195 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-20195 being exploited?

There is no known exploitation of CVE-2026-20195 in the wild and no public exploit code.

All Cisco Identity Services Engine vulnerabilities

Sources

Also known as GHSA-63pc-j336-8qq4.