CVE-2026-40379

Azure Entra ID Spoofing Vulnerability

Published May 12, 2026 CVSS 3.1 · 9.3 Critical EPSS < 1% KEV · Not listed
Description
Exposure of sensitive information to an unauthorized actor in Azure Entra ID allows an unauthorized attacker to perform spoofing over a network.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Microsoft entra Id
CPEs cpe:2.3:a:microsoft:entra_id:-:*:*:*:*:*:*:*
Vendors & Products Microsoft entra Id
Type Values Removed Values Added
Title Microsoft Enterprise Security Token Service (ESTS) Spoofing Vulnerability Azure Entra ID Spoofing Vulnerability
First Time appeared Microsoft microsoft Entra Id
CPEs cpe:2.3:a:microsoft:azure_enterprise_security_token_service:*:*:*:*:*:*:*:* cpe:2.3:a:microsoft:microsoft_entra_id:*:*:*:*:*:*:*:*
Vendors & Products Microsoft microsoft Entra Id
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Exposure of sensitive information to an unauthorized actor in Azure Entra ID allows an unauthorized attacker to perform spoofing over a network.
Title Microsoft Enterprise Security Token Service (ESTS) Spoofing Vulnerability
First Time appeared Microsoft
Microsoft azure Enterprise Security Token Service
Weaknesses CWE-200
CPEs cpe:2.3:a:microsoft:azure_enterprise_security_token_service:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft azure Enterprise Security Token Service
References
Metrics cvssV3_1

{'score': 9.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N/E:U/RL:O/RC:C'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
microsoft
Published
Updated
Aug 10, 2026, 3:12 PM
Reserved
Apr 11, 2026, 11:06 PM
Status
Analyzed
Published
May 12, 2026, 6:17 PM
Modified
Oct 26, 2026, 6:10 PM