Researcher Nightmare Eclipse released ShieldCrash, a Microsoft Defender zero-day PoC that bypasses September patches and reads files as SYSTEM.
Zero-day researcher Nightmare Eclipse (MSNightmare) published ShieldCrash, their 11th Microsoft zero-day, a proof-of-concept bypass of the ShieldBreak patch (CVE-2026-69414), which itself had bypassed the fix for RoguePlanet (CVE-2026-50656). ShieldCrash works on Windows 10, Windows 11, and Windows Server systems that have applied the September 2026 patches and allows arbitrary file reads as SYSTEM, though not arbitrary writes or a full SYSTEM shell. Microsoft has not said when it plans to patch the issue. The researcher recently also released zero-days affecting CrowdStrike Falcon (FalconFlank), Kaspersky endpoint antivirus (HardBreacher, patched), and Gen Digital's Avast (PrettyPrague).
Microsoft patched CVE-2026-69485, an 8.8 CVSS RCE flaw in the Windows Remote Desktop Client affecting Windows 10/11 and Server 2016-2025.
Microsoft's September 2026 updates fix CVE-2026-69485, an Important-rated remote code execution vulnerability (CVSS 3.1: 8.8, temporal 7.7) in the Windows Remote Desktop Client caused by use of an uninitialized resource. An authenticated attacker with low privileges could send a specially crafted network request to execute code on an affected server, with no user interaction required. Microsoft says the flaw was not publicly disclosed before patching and rates exploitation as 'Less Likely' with no evidence of active exploitation. Affected products span Windows Server 2016, 2019, 2022 and 2025 and Windows 10 (1607-22H2) and Windows 11 (23H2-26H1), with fixes delivered via KBs including KB5123099, KB5122876 and KB5122882.
Microsoft patched CVE-2026-69449, a heap-based buffer overflow in Windows BitLocker enabling code execution, affecting Windows 10/11 and Server 2012-2025 in September 2026 updates.
Microsoft disclosed CVE-2026-69449, a heap-based buffer overflow in Windows BitLocker rated Important, which could allow an authorized attacker to execute arbitrary code locally, with possible in-network exploitation via arbitrary endpoint calls. Microsoft rates exploitation as Less Likely and there was no public disclosure or in-the-wild exploitation at release. The flaw affects Windows 10 (1607-22H2), Windows 11 (23H2-26H1), and Windows Server 2012 through 2025, including Server Core. Fixes shipped in the September 2026 Patch Tuesday cumulative updates via platform-specific KBs such as KB5124012 and KB5122871.
Microsoft's September Patch Tuesday fixes a record 974 flaws, including two actively exploited Windows zero-days and critical DNS and Windows Shell bugs.
Microsoft released fixes for 974 vulnerabilities, its largest-ever monthly patch batch, bringing the 2026 total above 2,600. Two zero-day privilege elevation flaws, CVE-2026-81963 and CVE-2026-85880, are being actively exploited. Critical bugs include CVE-2026-69730, an unauthenticated DNS weakness in Windows Server 2012 onward and Windows 10 deemed likely to be exploited, and CVE-2026-69829, a CVSS 9.8 Windows Shell remote code execution flaw requiring no privileges or user interaction. Microsoft and other vendors credit AI-assisted discovery for the growing patch volumes.
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.
Actively exploited CVSS 9.8 Windows Netlogon flaw lets unauthenticated attackers execute code with SYSTEM privileges on domain controllers.
Microsoft's May 2026 advisory describes CVE-2026-41089, a stack-based buffer overflow in Windows Netlogon (CVSS 9.8) that allows unauthenticated remote code execution with SYSTEM privileges on domain controllers via specially crafted packets. The Centre for Cybersecurity Belgium reports the flaw is currently being exploited by threat actors. All Windows Server versions from 2012 through 2025 acting as domain controllers are affected and require the May updates.
CISA warns CVE-2026-33824, a critical unprivileged RCE in Windows IKE Extension, is now actively exploited.
CVE-2026-33824 is a critical remote code execution vulnerability in the Windows IKE Extension affecting all supported Windows 10, Windows 11, and Windows Server releases. The flaw allows unprivileged attackers to gain code execution on affected systems. CISA has flagged the vulnerability as actively exploited in attacks, indicating a KEV addition and urgent patching priority for Windows environments.
Local Privilege Escalation via Link Following in Windows Update Stack
CVE-2026-81963 is a link-following flaw (CWE-59, improper link resolution before file access) in the Microsoft Windows Update Stack, in which the component fails to correctly resolve file links before opening them. A local attacker with low privileges can plant or manipulate a link (symlink/junction) that the privileged update stack follows during operation, redirecting its file access to an attacker-controlled target. The result is local privilege escalation — CVSS 3.1 rates this 7.8 (high) with high confidentiality, integrity, and availability impact — allowing an authorized local user or malware already on the machine to gain elevated rights. Affected products are Windows 11 23H2, 24H2, 25H2, and 26H1 and Windows Server 2025; any unpatched system on those versions is exposed to any local account holder. The flaw was fixed in Microsoft's record September 2026 Patch Tuesday (974 CVEs), was added to CISA's KEV on 2026-09-08 as one of two Windows zero-days reported as exploited in the wild, and has no known public PoC or confirmed ransomware use.
· Microsoft Windows 11 23H2, 24H2, 25H2, 26H1 · Microsoft Windows Server 2025 KEVmass
Heap-Based Buffer Overflow in Windows ALPC Enables Local Privilege Escalation
CVE-2026-85880 is a heap-based buffer overflow in Windows Advanced Local Procedure Call (ALPC), the Windows mechanism for local inter-process communication. An authorized local attacker can trigger the overflow by submitting crafted input over ALPC, corrupting heap memory in the component that handles the request. Successful exploitation allows the attacker to execute code with elevated privileges, typically gaining SYSTEM-level control of the local host, which is especially valuable as a post-exploitation or sandbox-escape step. Affected products include Windows 10 (1607, 1809, 21H2, 22H2) and Windows Server 2012, 2016, 2019, and 2022, meaning most on-premises Windows estates are in scope. The flaw was fixed in Microsoft's record 974-CVE September 2026 Patch Tuesday and was added to CISA's KEV on 2026-09-08, confirming exploitation in the wild; press reports describe Windows zero-days being chained with a Chrome zero-day in 'BlueMoon' kit attacks, though the data does not explicitly confirm this CVE is the Windows flaw in that chain.
· Microsoft Windows 10 1607, 1809, 21H2, 22H2 · Microsoft Windows Server 2012, 2016, 2019, 2022 KEVmass
Unauthenticated Double-Free RCE in Microsoft Windows IKE Extension
A double-free memory-corruption flaw (CWE-415) in the Microsoft Windows Internet Key Exchange (IKE) service extension allows a remote, unauthenticated attacker to trigger the bug with crafted network traffic, with no privileges or user interaction required. Successful exploitation yields remote code execution with full system impact, reflected in the critical 9.8 CVSS score (high confidentiality, integrity, and availability). The vulnerable IKE component is present in Windows 10 (1607, 1809, 21H2, 22H2), Windows 11 (23H2, 24H2, 25H2, 26H1), and Windows Server 2016, 2019, and 2022 (including 23H2), which ship it as a built-in feature. CISA added the flaw to the Known Exploited Vulnerabilities catalog on 2026-08-18, and security reporting confirms it is being actively exploited in the wild, though ransomware use is not yet confirmed. No public proof-of-concept is known, but the high EPSS score (72.7%, 99th percentile) signals a very strong likelihood of imminent or ongoing exploitation.
· Microsoft Windows 10 1607 · Microsoft Windows 10 1809 KEVmass
Missing Authorization in Microsoft Entra ID Enables Privilege Escalation
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%.
Unauthenticated Stack Buffer Overflow RCE in Windows Server Netlogon (CVE-2026-41089)
CVE-2026-41089 is a stack-based buffer overflow (CWE-121) in the Netlogon service of Windows Server. An unauthenticated remote attacker can trigger it by sending crafted network requests to the Netlogon RPC interface, with no privileges or user interaction required per the CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N). Successful exploitation yields remote code execution with high confidentiality, integrity, and availability impact; on domain controllers, where Netlogon runs by default, this typically means compromise of a critical authentication server and risk of broader domain compromise. All organizations running the affected Windows Server versions (2012, 2016, 2019, 2022, 2022 23H2, and 2025) are in scope, with Active Directory domain controllers the highest-value targets. Microsoft fixed the flaw in its May 2026 Patch Tuesday release (138 vulnerabilities patched), and security reporting indicates the RCE is being exploited with domain controllers at risk; a public proof-of-concept is available, it is not yet in CISA KEV, and EPSS assigns a 79.6% probability of exploitation within 30 days.
· microsoft Windows Server 2012 · microsoft Windows Server 2016 PoC ×3mass
CVE-2026-69730 is a use-after-free memory corruption flaw (CWE-416) in the Windows DNS service that allows an unauthenticated, remote attacker to execute arbitrary code by sending crafted network traffic to the affected system. Because the flaw is network-exploitable with no privileges or user interaction required (CVSS 3.1 9.8), any system running the vulnerable DNS service is a direct target. Successful exploitation would give the attacker code execution in the context of the DNS service, which on Windows Server typically runs with high privileges such as SYSTEM, and could enable wormable spread between vulnerable hosts. Affected organizations are those running the Windows DNS Server role — a component deployed on virtually all Windows Server domain controllers and on dedicated Windows DNS servers, especially those exposed to untrusted networks. As of the September 2026 Patch Tuesday release, there is no known public proof-of-concept, the flaw is not listed in CISA's KEV, and it has not been confirmed exploited in the wild, though it was flagged among roughly 20 'wormable' bugs and described in press coverage as a successor to the 2020 SigRed Windows DNS RCE.
· Microsoft Windows DNS Server role (Windows Server)mass
Permissive Cross-Domain Policy Privilege Elevation in Microsoft Azure Arc
Microsoft Azure Arc (CVE-2026-62895) contains a privilege elevation flaw caused by a permissive cross-domain policy that trusts untrusted domains, mapped by Microsoft to CWE-942 (permissive cross-domain policy with untrusted domains), CWE-1390 (weak authentication) and CWE-89 (SQL injection). An unauthenticated attacker can exploit it over a network, with CVSS scoring indicating some user interaction is required (AV:N/AC:L/PR:N/UI:R), by abusing the overly permissive cross-domain trust to elevate privileges, with high impact on confidentiality, integrity and availability (CVSS 3.1: 8.8 High). Any organization using Azure Arc to manage hybrid or multi-cloud resources is potentially affected. There is no evidence of exploitation in the wild, no known public proof-of-concept, the flaw is not in CISA's KEV catalog, and EPSS estimates only a 0.7% probability of exploitation in the next 30 days (52nd percentile). Microsoft addressed the flaw as part of its September 2026 Patch Tuesday release, which fixed 966 flaws including 2 zero-days.
Insufficiently Protected Credentials in Microsoft Azure CycleCloud
CVE-2026-77909 is a credential-protection flaw (CWE-522) in Microsoft Azure CycleCloud, Microsoft's tool for creating and managing HPC clusters in Azure, in which credentials are stored or transmitted with insufficient protection. A remote attacker who already holds a low-privileged authorized account can trigger the flaw over the network, with no user interaction required. Because the CVSS scope is changed with high confidentiality impact, the exposed credentials can likely be used in another security scope — for example, to retrieve or reuse secrets that grant access to additional resources beyond the immediate component — resulting in information disclosure, though integrity and availability are unaffected. Organizations running Azure CycleCloud to orchestrate HPC workloads in their Azure subscriptions are affected. There is no known public proof-of-concept, it is not in the CISA KEV catalog, EPSS is a modest 0.6% over 30 days, and no in-the-wild exploitation has been reported; a fix was distributed as part of Microsoft's September 2026 Patch Tuesday, which addressed 966 flaws.
OS Command Injection Privilege Elevation in Microsoft Azure HDInsights
CVE-2026-81349 is an operating-system command injection flaw (CWE-78) in Microsoft's Azure HDInsights managed big-data service. It is triggered when the service improperly neutralizes special elements passed into an OS command, and per the CVSS vector an attacker must already hold high-level authorized access, exploiting it over the network with no user interaction required. Successful exploitation allows the attacker to elevate privileges, with high impact on the confidentiality, integrity, and availability of the affected HDInsight environment. Only organizations running Azure HDInsight clusters are affected; the flaw was fixed as part of Microsoft's September 2026 Patch Tuesday, which addressed 966 flaws. No public proof-of-concept is known, it is not listed in CISA's KEV catalog, and EPSS estimates roughly a 0.7% chance of exploitation within 30 days.
Microsoft is aware of an elevation of privilege in the Microsoft Malware Protection Engine in Microsoft Defender publicly referred to as "RoguePlanet ".
Microsoft is aware of an elevation of privilege in the Microsoft Malware Protection Engine in Microsoft Defender publicly referred to as "RoguePlanet ".
Entities are extracted by the model from each article. Watching an entity keeps it in this browser only (no account); the watchlist page and dashboard alerts use it.