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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.

Cisco Talos · 7d agoAdvisory in the wildCVE-2026-81963CVE-2026-85880CVE-2026-69676+27 CVEs

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 · 8d agoAdvisory in the wildCVE-2026-69805CVE-2026-58649CVE-2026-69806+27 CVEs1

ZDI-26-656: PAPPL Job Processing Heap-based Buffer Overflow Remote Code Execution Vulnerability

ZDI-26-656: Unauthenticated heap-based buffer overflow in PAPPL job processing allows remote code execution, rated CVSS 9.8.

The Zero Day Initiative published advisory ZDI-26-656 for PAPPL, the open-source printer application framework. A heap-based buffer overflow in job processing allows remote attackers to execute arbitrary code with no authentication required. ZDI assigned a CVSS 9.8 rating. No CVE identifier was listed in the advisory text.

ZDI Published Advisories · 6d agoAdvisory 2 sources

ZDI-26-632: WatchGuard FireWare OS epm connect Stack-based Buffer Overflow Remote Code Execution Vulnerability

ZDI disclosed a CVSS 8.8 unauthenticated stack-based buffer overflow in WatchGuard FireWare OS epm connect enabling network-adjacent remote code execution.

ZDI published advisory ZDI-26-632 for a stack-based buffer overflow in the epm connect component of WatchGuard FireWare OS. Network-adjacent attackers can execute arbitrary code without authentication. ZDI assigned CVSS 8.8 and the issue is tracked as CVE-2026-13086.

Pyramid Solutions NetStaX EtherNet/IP Stack

CISA flags critical CVE-2026-78012 (CVSS 9.8) stack buffer overflow in Pyramid Solutions NetStaX EtherNet/IP stacks below v5.6.1, risking crashes or remote attack vectors.

CISA republished Pyramid Solutions' advisory for CVE-2026-78012, a CWE-121 stack-based buffer overflow in the NetStaX EtherNet/IP stack versions prior to 5.6.1, scored CVSS 9.8. Large Class 3 explicit-message requests can exceed the application-side receive buffer without generating a CIP error, potentially causing memory corruption, device crashes, or a silent remote attack vector. All eight adapter and scanner DLL/development kit variants, including CIP Security editions, are affected across critical manufacturing, energy, water, and chemical sectors. No public exploitation has been reported.

CISA Advisories · 13d agoAdvisoryCVE-2026-78012

AL26-019 - Vulnerabilities impacting Citrix NetScaler ADC and NetScaler Gateway - CVE-2026-19490 and CVE-2026-19489

Canadian Cyber Centre alerts on Citrix NetScaler ADC/Gateway flaws CVE-2026-19490 (authentication bypass) and CVE-2026-19489 (buffer overflow), urging emergency patching.

The Canadian Centre for Cyber Security issued alert AL26-019 covering two Citrix NetScaler vulnerabilities disclosed in a vendor advisory on August 19, 2026. CVE-2026-19490 (CWE-288) allows a remote unauthenticated attacker to bypass authentication on appliances configured as a Gateway for SSL VPN, ICA Proxy, CVPN, RDP Proxy, or as an AAA virtual server. CVE-2026-19489 (CWE-120) is a classic buffer overflow that may cause memory overflow, unpredictable behavior, or denial-of-service conditions. Affected appliances are vulnerable when configured as a SAML IdP; fixed versions include 14.1-73.32, 13.1-63.21, and 13.1-37.277 for FIPS.

Microsoft Patch Tuesday for August 2026 Fixed a Zero

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.

Security Affairs · Aug 12, 2026Advisory in the wildCVE-2026-68820CVE-2026-62878CVE-2026-62893+5 CVEs

Heap overflow in kernel driver due to missing size validation

Fortinet fixes a CVSS 7.3 heap overflow in the FortiClient Windows kernel driver enabling code execution via crafted DNS responses.

Fortinet PSIRT advisory FG-IR-26-156, revised 2026-08-12, describes a heap-based buffer overflow (CWE-120, buffer copy without checking input size) in the FortiClient Windows kernel driver, scored CVSSv3 7.3. An unauthenticated attacker positioned to alter or craft DNS responses for a targeted host could execute arbitrary code via malicious packets. No CVE identifier or exploitation status is provided in the advisory text, so administrators should check the full bulletin for affected versions and fixed releases.

Fortinet PSIRT · Aug 12, 2026Advisory