ZeroHour

CVE-2026-83941

mass

Missing Authorization in Microsoft Entra ID Enables Privilege Escalation

CVSS 3.1
9.9 critical
EPSS
<1%p52
Published
()
Modified
AI analysis

CVE-2026-83941 is a missing-authorization flaw (CWE-862) in Microsoft Entra ID, the cloud identity service behind Microsoft 365 and Azure. An already-authenticated, low-privileged user can send a network request to an Entra ID endpoint that fails to enforce proper authorization checks, requiring no user interaction. Exploitation lets the attacker elevate their privileges within the directory, with high confidentiality and integrity impact (CVSS 9.9, scope changed). Any organization that uses Microsoft Entra ID is in the affected population. The flaw was patched in Microsoft's September 2026 Patch Tuesday release; it is not in CISA KEV, has no known public proof-of-concept, and carries a low EPSS of roughly 0.7%.

What to do: Review Microsoft's September 2026 Patch Tuesday advisory for this CVE and apply any required tenant-side updates or configuration changes, noting that fixes for the cloud-hosted directory service are applied largely by Microsoft. Audit privileged role assignments and sign-in activity in your tenant for signs of unexpected elevation, and tighten who holds elevated roles. Monitor for additions to CISA KEV or public proof-of-concept code, which would raise urgency.

Affected
Microsoft Entra ID (Azure Active Directory)
Estimated exposure
masshundreds of millions of user identities across hundreds of thousands of organizations (Entra ID underpins essentially all Microsoft 365/Azure tenants) — Entra ID is the default identity provider for Microsoft 365 and Azure, so virtually every organization using those platforms has tenants and users exposed to this flaw, though exploitation requires an attacker with existing low-privilege…

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

Description

Missing authorization in Entra ID allows an authorized attacker to elevate privileges over a network.

Weakness
CWE-862
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

In the news

Patch Tuesday - September 2026

Microsoft's September 2026 Patch Tuesday fixes 999 CVEs, a record, with two zero-day privilege escalation flaws already exploited in the wild.

Microsoft published 974 own-product vulnerabilities plus 25 non-Microsoft CVEs, totaling 999 — the most CVEs Microsoft has ever released in a single day. Two flaws are exploited in the wild: CVE-2026-85880, an out-of-bounds write in Windows ALPC granting SYSTEM privileges, and CVE-2026-81963, an improper link resolution flaw in the Windows Update Stack also leading to SYSTEM. Chrome's V8 zero-day CVE-2026-85046 was patched in Edge on September 2, but Microsoft had not published a corresponding advisory, leaving uncertainty about other Chromium fixes in Edge. October 14 lifecycle changes end servicing for Windows 11 24H2 Home/Pro, Office 2021, and Exchange Server 2016/2019.

Rapid7 Blog · 7d agoVulnerability in the wildCVE-2026-85880CVE-2026-81963CVE-2026-85046+10 CVEs

Microsoft Patch Tuesday Update September 2026 – 974 Vulnerabilities Fixed, Including 2 Zero-Days

Microsoft's September 2026 Patch Tuesday fixes 974 vulnerabilities across Windows and Office, including two actively exploited Windows privilege-escalation zero-days.

Microsoft's September 2026 Patch Tuesday addresses 974 vulnerabilities spanning Windows, Office, SQL Server, SharePoint, Exchange, Azure, and developer tools. Two Windows zero-days are confirmed exploited in attacks: CVE-2026-85880, a Windows ALPC elevation-of-privilege flaw, and CVE-2026-81963, a Windows Update Stack privilege-escalation flaw involving link following. The release also includes Critical fixes for Windows Secure Kernel Mode, VBS Enclave, Excel, and Word.

Microsoft September 2026 Patch Tuesday fixes 966 flaws, 2 zero-days

Microsoft's September 2026 Patch Tuesday fixes a record 966 flaws, including two Windows zero-days actively exploited to gain SYSTEM privileges.

Microsoft's September 2026 Patch Tuesday addresses a record 966 vulnerabilities, including 105 rated Critical, 81 of them remote code execution bugs. Two zero-days were actively exploited: a Windows Update Stack link-following flaw and a Windows ALPC heap-based buffer overflow, both allowing local elevation to SYSTEM privileges. The ALPC flaw was reported by Volexity and Proofpoint researchers, while the Update Stack flaw was credited to Romain Deperne and the Microsoft Threat Intelligence Centre. Microsoft shared no details on how the flaws were exploited in attacks.

BleepingComputer · 7d agoAdvisory in the wildCVE-2026-69805CVE-2026-58649CVE-2026-69806+27 CVEs1

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.