---
id: "CVE-2026-17202"
page: "https://infrastack.ai/live/CVE-2026-17202"
kind: "vulnerability"
aliases: ["CVE-2026-17202"]
title: "IBM API Connect: login responses let attackers enumerate valid usernames"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["api-gateway", "ibm-api-connect", "runtime", "self-hosted"]
not_affected_if: ["outside-affected-versions"]
published_at: "2026-11-07T05:18:30+00:00"
first_seen_at: "2026-11-07T05:46:00+00:00"
updated_at: "2026-11-07T05:54:12+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-17202", "first_seen_at": "2026-11-07T05:46:00+00:00"}]
exploit_sources: []
---

# IBM API Connect: login responses let attackers enumerate valid usernames

Link for people: https://infrastack.ai/live/CVE-2026-17202 (this .md is for agents)

IBM API Connect 12.1.0.0 through 12.1.1.2 returns observably different responses depending on whether a username exists. A remote attacker can use this to build a list of valid usernames for later password guessing or phishing.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed IBM API Connect version against the affected range 12.1.0.0 through 12.1.1.2.

## Timeline

- 2026-11-07T05:46:00+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-17202

## From the sources

IBM API Connect 12.1.0.0 through 12.1.1.2 could allow a remote attacker to enumerate usernames due to observable differences in response behavior.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_