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.
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).
Microsoft's September 2026 Patch Tuesday fixes a record 964 CVEs, including two zero-days actively exploited in the wild.
Microsoft patched a record 964 CVEs in its September 2026 Patch Tuesday release, with 101 rated critical and 824 rated important, making it the largest Patch Tuesday to date. The release includes fixes for two zero-days that were exploited in the wild, with CVE-2026-81963 and CVE-2026-85880 highlighted in the release. Affected products span Windows core components, Office, Exchange, .NET, Visual Studio, Active Directory services (including AD CS and AD FS) and numerous Azure services. Tenable notes the release surpasses July's as the biggest ever.
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.
Kaspersky reports Iran-linked Mirage Kitten delivers new NodeRabbit and PollCat malware to fintech and aviation targets via fake LinkedIn coding assessments.
Kaspersky researchers documented two previously undocumented Node.js malware families, NodeRabbit and PollCat, attributed with high confidence to Iran-linked APT group Mirage Kitten. The malware is delivered via fake recruiter personas on LinkedIn offering coding assessments hosted on Amazon S3, with instructions banning AI assistants so AI code-review tools would not flag the trojanized npm packages. NodeRabbit is cross-platform (Windows, Linux, macOS), uses AES-256-GCM-encrypted C2 on Azure, includes sandbox checks, and one variant installs a fake 'GitHub Copilot Helper' VS Code extension plus Git hook persistence. Victims identified so far are in fintech and aviation organizations across Egypt, Ethiopia, and Afghanistan.
Kaspersky links Iranian espionage group Mirage Kitten to fake job offers delivering new NodeRabbit and PollCat malware at aviation and fintech targets.
Kaspersky attributes the campaign to Iran-linked Mirage Kitten (also tracked as UNC1549, Smoke Sandstorm and Nimbus Manticore), which targeted developers and specialists in Egypt, Ethiopia and Afghanistan via fake recruiter contacts on LinkedIn and job platforms. Victims were lured into running malicious coding assessments that deployed two previously unknown families: NodeRabbit, a cross-platform RAT for Windows, Linux and macOS, and PollCat, which provides persistence and delivers additional payloads. The group masks activity behind legitimate Microsoft Azure and Cloudflare infrastructure, sometimes embedding victim organization names in Azure subdomains. The group has been active since at least 2022, focusing on aviation, aerospace and financial technology sectors in Africa and the Middle East.
Canada's Cyber Centre updated advisory AV26-804 relaying Microsoft's August 2026 monthly rollup of vulnerabilities across .NET and Azure products.
The Canadian Centre for Cyber Security advisory AV26-804, updated August 27, 2026, relays Microsoft's August 2026 monthly security rollup originally issued August 11. Affected products include .NET 8.0, 9.0, and 10.0 on Linux, macOS, and Windows, plus many Azure services. Listed Azure components include Azure Kubernetes Service, Azure SQL Database, Azure Service Bus, Azure Active Directory, Azure Logic Apps, and Azure Monitor Agent.
Microsoft patched critical Entra ID RCE CVE-2026-69836 (CVSS 10.0), fully mitigated server-side with no customer action; no in-the-wild exploitation confirmed.
Microsoft patched CVE-2026-69836, a critical (maximum CVSS 10.0) unauthenticated remote code execution flaw in Entra ID caused by deserialization of untrusted data over a network. Entra ID, formerly Azure Active Directory, is Microsoft's cloud identity service verifying logins and controlling access to Microsoft 365, Azure, and connected third-party apps. The flaw was discovered by Microsoft Principal Security Engineer Robert Fitzpatrick and fully mitigated server-side, requiring no customer action. Microsoft initially reported the bug as exploited, but later changed the status to 'no' and confirmed the vulnerability was not exploited in the wild.
Tenable details ransomware group Storm-0501's Azure tenant-hijacking tactics and how its cloud detection and response identifies them.
Tenable's blog describes how cybercrime group Storm-0501 conducts cloud-first ransomware campaigns against Azure environments. The group has shifted from endpoint encryption to total hijacking of cloud tenants and systematically neutralizes resource locks, immutability policies, and backups. Tenable outlines its One Cloud Exposure detections, using AI-powered threat stories and precision alerts, to expose these TTPs early.
A seller offers 1.7 million McDonald's employee records allegedly taken from its Azure tenant via compromised credentials; an 8,000-row sample verifies as genuine.
A forum seller named TheHatman posted an 8,000-row sample of McDonald's employee directory data, claiming a 1.7 million-record haul pulled directly from the company's Azure tenant using compromised credentials. Ransomnews analysis found authentic Entra ID export artifacts, including genuine domains, tenant-internal addresses, encoding errors, and truncated HR fields, but could not verify the data's age or the 1.7 million figure. The same seller listed nine datasets in 16 days covering about 3.6 million records across McDonald's, Vodafone, Gap, hotels, and IT outsourcers, suggesting infostealer-driven credential resale. No passwords or hashes appear in the sample, so the primary risk is social engineering.
Microsoft's August 2026 Patch Tuesday fixes 398 CVEs, including an actively exploited WinSock zero-day CVE-2026-68820 and wormable DNS RCE CVE-2026-62878.
Microsoft's August 2026 Patch Tuesday addresses 398 CVEs across Windows, Office, Azure, Exchange Server, SharePoint, Teams, .NET and other products, with 62 rated Critical. The actively exploited CVE-2026-68820 is a use-after-free in the Windows WinSock afd.sys driver that can yield SYSTEM privileges via a race condition. CVE-2026-62878 is a critical, wormable stack buffer overflow in Windows DNS Server allowing unauthenticated, remote code execution without user interaction. Other notable fixes include WDS TFTP RCE CVE-2026-62893, a QUIC flaw affecting roughly 13.5 million sites (CVE-2026-62815), an Exchange authentication bypass EoP demonstrated at Pwn2Own Berlin (CVE-2026-62911), and two TPM 2.0 reference implementation fixes.
Tenable reports Microsoft's August 2026 Patch Tuesday addresses 398 CVEs including three zero-days, one exploited in the wild (CVE-2026-68820).
Microsoft patched 398 CVEs in its August 2026 Patch Tuesday release, with 42 rated critical, 355 important, and one moderate, and three zero-days among them. One zero-day is confirmed as exploited in the wild. The release covers components including .NET, .NET Framework, Active Directory Certificate Services (AD CS), Azure services, and Windows. Tenable's count omits two CVEs assigned by MITRE, CVE-2026-6726 and CVE-2026-6727.
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
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
Use-After-Free Local Privilege Escalation in Microsoft Windows WinSock AFD Driver
CVE-2026-68820 is a use-after-free (CWE-416) in the Windows Ancillary Function Driver for WinSock (afd.sys), the kernel component that handles Winsock socket operations. A local, authenticated attacker can trigger the memory corruption through crafted socket activity, and the high attack-complexity score (AV:L/AC:H/PR:L) indicates exploitation requires a specific, likely race-sensitive sequence of operations. Successful exploitation elevates privileges to SYSTEM, giving the attacker full control of the host, and public reporting describes deployment of a backdoor after privilege escalation. Virtually every Windows 10, Windows 11, and Windows Server (2012-2022) installation ships this driver, so the affected population is essentially the entire supported Windows installed base. The flaw is being exploited in the wild: CISA added it to the KEV on 2026-08-11, Microsoft fixed it in the August 2026 Patch Tuesday release, and reporting ties active exploitation to North Korea's Lazarus group, who paired the zero-day with fake job-offer lures.
· Microsoft Windows Ancillary Function Driver for WinSock (afd.sys) as shipped with the Windows versions listed below · Microsoft Windows 10 1607, 1809, 21H2, 22H2 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%.
Improper Authentication in Microsoft Authenticator Enables Local Privilege Escalation
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.
Capture-replay authentication bypass in Microsoft MSAL for Node.js
CVE-2026-84003 is an authentication bypass by capture-replay (CWE-294) in the Microsoft Authentication Library (MSAL) for Node.js, the library Node.js applications use to authenticate users and services against Microsoft's identity platform. An attacker positioned on the network who can capture authentication material in transit can replay it to authenticate as a legitimate user or client, with no privileges or user interaction required; the high attack complexity reflects the difficulty of intercepting and replaying the exchange while it remains valid. Successful exploitation enables spoofing with high impact on confidentiality and integrity (the attacker can act as the victim), though there is no availability impact. Any organization running Node.js server applications, APIs, daemons, or CLIs that depend on MSAL for Node.js is affected, with end users of those applications exposed through them. As of this writing there is no known public proof-of-concept, the flaw is not in CISA KEV, and EPSS puts the 30-day exploitation probability at 0.4% (37th percentile); the fix shipped in Microsoft's September 2026 Patch Tuesday.
· Microsoft Authentication Library (MSAL) for Node.js (@azure/msal-node)mass
Untrusted Pointer Dereference LPE in Windows Secure Kernel Mode
CVE-2026-83939 is an untrusted pointer dereference (CWE-822) in the Windows Secure Kernel Mode, the high-privilege virtualization-based security component of Windows. A local attacker who is already authorized and holds high privileges on the system can trigger the flaw by causing the Secure Kernel to dereference an attacker-influenced pointer, gaining local elevation of privileges. Because the CVSS scope is 'changed' (S:C), the flaw lets an attacker cross a security boundary beyond the process they started in, with high impact on confidentiality, integrity and availability. Any Windows installation whose Secure Kernel component is affected is at risk, per Microsoft's September 2026 Patch Tuesday advisory; exact version ranges are listed in Microsoft's bulletin. There is no known in-the-wild exploitation, no public proof-of-concept, and a low 0.3% EPSS probability of exploitation in the next 30 days, but a fix shipped as part of the 974-vulnerability September 2026 release.
· Microsoft Windows (Secure Kernel Mode component)mass
Local Privilege Escalation via Link Following in Windows User Profile Service
CVE-2026-62832 is a local privilege escalation flaw (CWE-59, improper link resolution, or 'link following') in the Windows User Profile Service. An attacker who already holds a limited local account on an affected machine can cause the service to follow a symbolic link or junction before it validates file access, so the service performs file operations with elevated rights. Successful exploitation grants elevated privileges on the local system — typically up to administrator/SYSTEM level — with no user interaction required. Affected platforms include Windows 10 21H2 and 22H2, Windows 11 23H2 through 26H1, and Windows Server 2022 and 2025, which together span essentially the entire supported Windows estate. As of this analysis there is no public proof-of-concept, no CISA KEV listing, and no confirmed in-the-wild exploitation of this specific flaw; EPSS estimates a 3.3% (88th percentile) chance of exploitation within 30 days, although Microsoft's August 2026 Patch Tuesday fixed 400+ vulnerabilities and a separate zero-day (CVE-2026-68820) is under active attack.
· microsoft Windows 10 21H2 · microsoft Windows 10 22H2mass
Out-of-bounds Read in Windows Kerberos KDC Enables Network Denial of Service
CVE-2026-84001 is an out-of-bounds read (CWE-125) in the Windows Key Distribution Center (KDC), the Kerberos authentication component built into Windows. An unauthorized, remote attacker can trigger it by sending specially crafted network requests to the KDC service, causing the service to read beyond allocated memory. According to the CVSS vector, the impact is availability-only (C:N/I:N/A:H): the attacker gains denial of service, not code execution, data theft, or tampering, though taking down the KDC on domain controllers can disrupt Kerberos authentication for an entire Active Directory domain. Any Windows system running the KDC is affected, chiefly Windows domain controllers and servers, although the specific affected Windows version ranges are not enumerated in the available data. There is no known public proof-of-concept, the CVE is not in CISA's KEV catalog, and its EPSS probability of ~0.6% suggests exploitation risk is currently low; the fix shipped in Microsoft's September 2026 Patch Tuesday release.
· Microsoft Windows (Key Distribution Center / Kerberos KDC service, primarily on Windows domain controllers and servers)mass
Out-of-Bounds Read in Windows Virtualization-Based Security (VBS) Enclave
An out-of-bounds read (CWE-125) in the Windows Virtualization-Based Security (VBS) Enclave allows a locally authenticated, low-privilege attacker to read memory beyond the enclave's intended boundary. It is triggered by code running locally under an authorized account that interacts with the enclave, with no user interaction required. The result is information disclosure only - potentially leaking data the enclave was meant to isolate, such as secrets or protected content - with no impact on integrity or availability. Any Windows system with VBS Enclave support is affected; Microsoft patched the issue in its September 2026 Patch Tuesday release, which fixed 974 vulnerabilities. No public proof-of-concept exists, the flaw is not in CISA's KEV catalog, and EPSS assigns roughly a 0.3 percent 30-day exploitation probability, so no exploitation is currently known.
· Microsoft Windows Virtualization-Based Security (VBS) Enclavemass
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