Microsoft August 2026 Patch Tuesday: 400 Flaws Fixed, Including an Actively Exploited Zero-Day

Microsoft has issued security updates for 400 flaws, including 42 vulnerabilities rated as "Critical," as part of the Patch Tuesday updates for August 2026. While slightly smaller than last month's record-breaking 570-flaw release, this remains an exceptionally large cycle, and it is further proof that the elevated pace Microsoft warned about is here to stay. The volume is being driven by an ongoing wave of AI-assisted vulnerability discovery, alongside three zero-day flaws that require immediate attention.

Zero-Days Fixed

Microsoft confirmed the inclusion of three zero-day flaws this month, one of which was actively exploited in the wild by a nation-state threat actor prior to a patch being available. These require prioritised, out-of-band deployment:

• CVE-2026-68820 - Windows Ancillary Function Driver for WinSock Elevation of Privilege (actively exploited, linked to a North Korean threat group deploying kernel-mode rootkit malware)
• CVE-2026-62832 - Windows User Profile Service Elevation of Privilege (publicly disclosed, tracked as "LegacyHive")
• CVE-2026-72971 - Windows Container Isolation FS Filter Driver Tampering (publicly disclosed)

Critical Vulnerabilities to Prioritise

Out of the 400 flaws, 42 received a "Critical" rating, with several carrying CVSS scores of 9.8 or higher. The following require immediate mitigation:

• CVE-2026-62893 - Windows Deployment Services TFTP Server RCE (CVSS 9.8, unauthenticated, exploitation assessed as "more likely")
• CVE-2026-65665 - Microsoft SharePoint Server RCE (CVSS 8.8, network exploitable, low privileges required)
• CVE-2026-62823 - Windows DHCP Server RCE (CVSS 8.8, exploitation assessed as "more likely")
• CVE-2026-62815 - Microsoft QUIC RCE
• CVE-2026-62817, CVE-2026-62820, CVE-2026-65789, CVE-2026-62878 - Windows DNS Server RCE (four separate critical flaws)
• CVE-2026-59118 - Microsoft Power Apps Elevation of Privilege
• CVE-2026-63508 - Microsoft Planetary Computer Pro Elevation of Privilege (CVSS 10.0)

Vulnerabilities by Category

The August 2026 updates addressed a total of 400 flaws, categorised as follows:

• Elevation of Privilege Vulnerabilities - 176
• Remote Code Execution Vulnerabilities - 110
• Information Disclosure Vulnerabilities - 86
• Denial of Service Vulnerabilities - 12
• Security Feature Bypass Vulnerabilities - 11
• Spoofing Vulnerabilities - 21
• Total Flaws - 400

Need Help with Patch Management?

Struggling to keep pace with monthly patch volumes like this? In 2026, "good enough" security is no longer an option. NOCTeam can secure your environment with proactive Patch Management, M365 hardening, and advanced Endpoint Detection and Response (EDR) services. Email [email protected] or visit our website nocteam.co.uk today for a free security checkup of your IT systems.

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Originally published on LinkedIn.