ZeroHour

CVE-2026-80097

mass

Improper Authentication in Microsoft Authenticator Enables Local Privilege Escalation

CVSS 3.1
8.6 high
EPSS
<1%p33
Published
()
Modified
AI analysis

CVE-2026-80097 is an improper authentication flaw (CWE-287) in Microsoft Authenticator that allows an unauthorized attacker to elevate privileges locally, rated 8.6 (high) with no privileges required, required user interaction, and a changed scope. Exploitation requires local access to a device running the app plus user interaction, and because the scope is changed, a successful attack crosses a security boundary beyond the Authenticator component itself. A successful exploit yields local privilege elevation with high impact to confidentiality, integrity, and availability. Anyone running affected versions of Microsoft Authenticator is affected; the app is Microsoft's standard multi-factor authentication app for Entra ID/Microsoft 365 and is widely deployed across enterprise and personal mobile devices. As of the September 2026 disclosure it is not known to be exploited - no public PoC, not in CISA KEV, EPSS 0.4% (33rd percentile) - and it was patched amid the record 974-flaw Patch Tuesday, though the two actively exploited zero-days in that release are Windows flaws, not this one.

What to do: Update Microsoft Authenticator through its usual app-store distribution channels (iOS App Store/Google Play) to the build released with September 2026 Patch Tuesday, and verify updated versions across the fleet via MDM or app inventory; specific patched build numbers were not provided in the source data. Prioritize shared workstations, kiosks, and hot-desked or BYOD endpoints where unprivileged local users interact with the app. No public PoC or in-the-wild exploitation is known, so routine prompt patching is appropriate.

Affected
Microsoft Authenticator
Estimated exposure
mass≈100M+ users/devices (Microsoft's standard MFA app, with app-store install counts on the order of hundreds of millions) — Microsoft Authenticator is the default MFA app deployed to Microsoft Entra ID/Microsoft 365 users, and public app-store listings show on the order of 100M+ installs, so the affected install base plausibly reaches the hundreds of millions,…

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

Description

Improper authentication in Microsoft Authenticator allows an unauthorized attacker to elevate privileges locally.

Weakness
CWE-287
Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

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 Patches Record 974 Flaws, Including Two Exploited Windows Zero-Days

Microsoft's September Patch Tuesday fixed a record 974 flaws, including two Windows privilege-escalation zero-days actively exploited and added to CISA's KEV catalog.

Microsoft's September 2026 Patch Tuesday addressed a record 974 vulnerabilities (999 including 25 non-Microsoft CVEs), with over 110 rated critical; 723 affect Windows and 111 affect Office. Two Windows privilege-escalation zero-days are actively exploited: CVE-2026-85880, an ALPC heap-based buffer overflow, and CVE-2026-81963, an improper link resolution flaw in the Windows Update Stack, both allowing attackers to gain SYSTEM privileges. CISA added both flaws to its KEV catalog, giving federal civilian agencies until September 22, 2026 to apply fixes. Volexity, Proofpoint, MSTIC, and independent researchers were credited with the reports; notable additional fixes include network-reachable RCEs in Exchange, SharePoint, SQL Server, Remote Desktop Services, DNS, and DHCP.

The Hacker News · 6d agoExploit / PoC in the wildCVE-2026-85880CVE-2026-81963CVE-2026-55007+9 CVEs

Microsoft Patches Record 974 Vulnerabilities, Including Two Exploited Zero-Days

Microsoft's September 2026 Patch Tuesday fixes a record 974 CVEs, including two Windows zero-days exploited in the wild for privilege escalation.

Microsoft patched 974 vulnerabilities, its largest Patch Tuesday ever, including CVE-2026-85880, a heap buffer overflow in Windows ALPC allowing AppContainer sandbox escape to System, and CVE-2026-81963, a link-following flaw in the Windows Update Stack enabling local privilege escalation. Both were exploited as zero-days before the patch. ZDI's Dustin Childs says 20 of the fixed flaws are wormable, enabling unauthenticated remote code execution. The release also covers 723 Windows flaws and 222 Office bugs, plus fixes in Exchange, SharePoint, SQL Server, Azure and Exchange Server RCE (CVE-2026-55007).

SecurityWeek · 7d agoExploit / PoC in the wildCVE-2026-85880CVE-2026-81963CVE-2026-55007+5 CVEs