CVE-2026-40379: Azure Entra ID Spoofing Vulnerability

Published May 7, 2026
·
Updated

Azure Entra ID Spoofing Vulnerability

Other sources

Exposure of sensitive information to an unauthorized actor in Azure Entra ID allows an unauthorized attacker to perform spoofing over a network.

NVD

Affected Software

3 affected components
Microsoft Enterprise Security Token Service (ESTS)
Microsoft Entra ID
Microsoft Entra ID

Event History

May 7, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeaknessAffected Software
Updated
via Microsoft·02:00 PM
Description
Updated
via Microsoft·02:00 PM
Affected Software
May 12, 2026
CVE Published
via MITRE·04:58 PM
Data Sourced
via MITRE·04:58 PM
DescriptionSeverity
Data Sourced
via NVD·06:17 PM
DescriptionSeverityWeaknessAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2026-40379?

CVE-2026-40379 has been classified as a critical vulnerability due to its potential to allow unauthorized spoofing attacks.

2

How do I fix CVE-2026-40379?

To fix CVE-2026-40379, ensure that the latest security updates and patches for Microsoft Enterprise Security Token Service (ESTS) are applied.

3

What impact does CVE-2026-40379 have on network security?

CVE-2026-40379 can lead to unauthorized access and potential data breaches by allowing attackers to exploit security tokens.

4

Who is affected by CVE-2026-40379?

Organizations using Microsoft Enterprise Security Token Service (ESTS) are affected by CVE-2026-40379.

5

What are the symptoms of CVE-2026-40379 exploitation?

Symptoms of exploitation may include unauthorized access attempts and unusual authentication patterns within network systems.

Contact

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