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

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

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 May 2026
- **Updated:** 6 May 2026
- **Also known as:** GHSA-63pc-j336-8qq4

## 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 (Observable Response Discrepancy)

## Which versions are affected by CVE-2026-20195?

It affects 1 product.


Products: 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.

## Other vulnerabilities in Cisco Identity Services Engine

- [CVE-2026-76460](https://insights.sbomify.com/CVE-2026-76460/): Cisco Identity Services Engine Incorrect Use of Privileged APIs (critical 10.0, exploited in the wild)
- [CVE-2025-20337](https://insights.sbomify.com/CVE-2025-20337/): Cisco Identity Services Engine Injection (critical 10.0, exploited in the wild)
- [CVE-2025-20281](https://insights.sbomify.com/CVE-2025-20281/): Cisco Identity Services Engine Injection (critical 10.0, exploited in the wild)
- [CVE-2026-20130](https://insights.sbomify.com/CVE-2026-20130/): Cisco Identity Services Engine Hardening Release - Improper Neutralization Vulnerabilities (critical 10.0)
- [CVE-2026-20192](https://insights.sbomify.com/CVE-2026-20192/): Cisco Identity Services Engine Hardening Release - Access Control Vulnerabilities (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-20195 and fix it if it is affected.

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

Affected product: Cisco Identity Services Engine. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-20195/ (Markdown: https://insights.sbomify.com/CVE-2026-20195/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20195
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20195
- OSV: https://osv.dev/vulnerability/CVE-2026-20195

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-20195/
Summaries are generated and may contain mistakes; the official description above is the record.