ZeroHour

CVE-2026-62916

mass

Authentication Bypass in Microsoft Entra ID Enables Privilege Elevation

CVSS 3.1
9.8 critical
EPSS
<1%p47
Published
()
Modified
AI analysis

CVE-2026-62916 is an authentication bypass (CWE-288) in Microsoft Entra ID, Microsoft's cloud identity and access management service, in which an alternate path or channel allows authentication checks to be circumvented. Per the CVSS vector, it is exploitable remotely over a network with no privileges and no user interaction required, by authenticating via an alternate path instead of the standard sign-in flow. A successful unauthenticated attacker gains the ability to elevate privileges, with high impact on confidentiality, integrity, and availability reflected in the 9.8 critical score. The affected population includes organizations relying on Entra ID, which is the default identity platform for Microsoft 365, Azure, and hybrid deployments; the available data does not specify affected versions or the specific sub-component involved. There is no public proof-of-concept, no confirmed in-the-wild exploitation, and the CVE is not in CISA's KEV; EPSS assigns a 0.6% probability of exploitation within 30 days.

What to do: Since Entra ID is a cloud service patched centrally by Microsoft, verify that the September 2026 security updates have been applied to your tenant and follow the Microsoft advisory for any tenant-side configuration or conditional access actions; no workarounds are documented in the available data. Review Entra ID sign-in and audit logs for unexpected privileged authentication activity, and re-check exposure after any additional Microsoft guidance on affected flows.

Affected
Microsoft Entra ID
Estimated exposure
masshundreds of millions of user identities across millions of Microsoft 365/Azure tenant organizations — Entra ID (formerly Azure AD) is the default identity service for Microsoft 365, Azure, and most Microsoft cloud offerings, so effectively every Microsoft cloud tenant and its users fall within the potential blast radius, supporting an…

Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.

Description

Authentication bypass using an alternate path or channel in Microsoft Entra ID allows an unauthorized attacker to elevate privileges over a network.

Vendors
microsoft
Products
entra id
Weakness
CWE-288
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

In the news

Microsoft Patch Tuesday, September 2026 Security Update Review

Microsoft's September 2026 Patch Tuesday fixes 974 vulnerabilities, including 113 critical and two actively exploited Windows privilege escalation flaws.

Microsoft's September 2026 Patch Tuesday fixes 974 vulnerabilities, its largest release ever, including 113 critical and 860 important, covering Windows HTTP.sys, Hyper-V, Entra ID, Exchange Server, Office, DNS, and more. Two zero-days are confirmed exploited in the wild: CVE-2026-81963 (Windows Update Stack EoP) and CVE-2026-85880 (ALPC heap overflow), both letting authenticated attackers gain SYSTEM privileges. Notable criticals include an Entra ID authentication bypass (CVE-2026-62916) and multiple Windows DNS Server and Office remote code execution flaws.

The September 2026 Security Update Review

ZDI's September 2026 Microsoft update review lists two already-exploited Windows EoP zero-days and dozens of critical RCEs across Office, SQL Server, and Windows services.

The review catalogs Microsoft's September 2026 fixes, marking CVE-2026-85880 (Windows ALPC) and CVE-2026-81963 (Windows Update Stack) as already exploited elevation-of-privilege issues. It also lists critical RCE flaws in Office, Word, Excel, PowerPoint, Outlook, SQL Server, Windows DNS, DHCP and Failover Cluster, plus graphics component RCEs. Azure-side fixes include Entra ID, Copilot Studio, Azure AI Language and Azure AD B2C elevation-of-privilege flaws.