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.
DDRop Attack Forces Intel TDX Confidential VMs Into Debug Mode and Exposes Memory
KU Leuven and ETH Zurich researchers released DDRop PoC hardware that forces Intel TDX confidential VMs into debug mode and exposes plaintext memory.
Researchers from KU Leuven, ETH Zurich, Google, and Durham University published proof-of-concept code, hardware designs, and firmware for DDRop, a DDR5 interposer that injects parity errors to drop selected cache-line writebacks. Because Intel TDX, Intel Scalable SGX, and AMD SEV-SNP lack per-line cryptographic freshness, processors decrypt and accept stale DRAM contents as current state. The PoC flips a victim's ATTRIBUTES.DEBUG flag to enable TDX debug mode, then copies victim memory in plaintext and can forge attestation reports. Affected environments include Intel 5th- and 6th-generation Xeon Scalable with TDX; Intel says the attack falls outside its cloud-computing threat model.
Microsoft September 2026 Patch Tuesday Fixes 973 Vulnerabilities and 2 Exploited Zero-Days
Microsoft's September 2026 Patch Tuesday fixes 973 vulnerabilities, including two zero-days already exploited in the wild.
Microsoft's September 2026 Patch Tuesday addresses 973 vulnerabilities across Windows, Office, and Azure components, including two zero-days already exploited in the wild. CVE-2026-81963, an elevation of privilege flaw in the Windows Update Stack, is flagged as an exploited zero-day. The release includes numerous remote code execution and information disclosure fixes for Microsoft Excel and Word, plus patches for the Windows kernel, ALPC, Print Spooler, ReFS, Entra ID, and Azure CLI.
Microsoft Patch Tuesday for September 2026 — Snort rules and prominent vulnerabilities
Microsoft's September 2026 Patch Tuesday fixes 973 vulnerabilities, including 113 critical, with two Windows privilege-escalation bugs (CVE-2026-81963, CVE-2026-85880) exploited in the wild.
Microsoft's September 2026 security update addresses 973 vulnerabilities across its product lineup, 113 rated critical, of which 82 are remote code execution flaws. Two vulnerabilities are confirmed exploited in the wild: CVE-2026-81963, an elevation-of-privilege flaw in the Windows Update Stack (CVSS 7.8), and CVE-2026-85880, a heap-based buffer overflow in Windows Advanced Local Procedure Call (CVSS 7.8). Microsoft flags several bugs as more likely to be exploited, including a 9.8 RCE in Windows DNS Server (CVE-2026-69730), an 8.8 RCE in Windows Kerberos (CVE-2026-69676), and a 9.0 EoP in Spring Cloud Azure (CVE-2026-69854). Cisco Talos published accompanying Snort rules to detect exploitation attempts against the prominent 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.
Windows 11’s strongest security defenses can be bypassed without a screwdriver
Researchers found a script-only attack, 'Download More RAM', that rewrites DIMM configuration chips to bypass Windows 11 VBS and HVCI security boundaries.
Researchers at the University of Birmingham and Durham University showed that overwriting configuration data on unprotected DDR4/DDR5 module chips creates memory aliases that let attackers with existing privileged access defeat Virtualisation-based Security and HVCI, re-enable blocklisted drivers, kill EDR, and bypass group policy. Microsoft assigned CVE-2026-23670 and shipped mitigations in its April 2026 updates; systems with Secure Boot enabled are protected. Affected unprotected product lines are estimated at more than half of the high-performance consumer memory market and over 70% of the gaming segment.