Microsoft on Tuesday announced patches for 421 CVEs, including a high-severity vulnerability that has been exploited in the wild as a zero-day.
The exploited flaw, tracked as CVE-2026-68820, is described as a use-after-free issue in Ancillary Function Driver for WinSock (afd.sys), the kernel-mode driver functioning as the backbone for the Windows Sockets API.
Microsoft says threat actors have been exploiting the security defect to elevate their privileges to System, without sharing details on the observed attacks.
“A locally authenticated attacker could run a specially crafted application on an affected system to trigger a race condition. Successful exploitation could allow the attacker to gain SYSTEM privileges. User interaction is not required,” the tech giant explains.
According to Tenable senior staff research engineer Satnam Narang, based on historical tradecraft targeting afd.sys flaws, the CVE might have been exploited by nation-state threat actors.
“Since 2022, there have been three other afd.sys zero-days exploited in the wild, including CVE-2025-32709, CVE-2025-21418, and CVE-2024-38193. CVE-2024-38193 was reportedly exploited by North Korean hackers linked to the Lazarus group,” Narang said.
As part of the August 2026 Patch Tuesday release, Microsoft also drew attention to CVE-2026-62832, an improper link resolution before file access (link following) bug in Windows’s User Profile Service, which could allow attackers to elevate their privileges locally.
“An authenticated attacker who has credentials for another local account could run a specially crafted application to load another user’s registry hive. Successful exploitation could allow the attacker to access or modify another user’s data and gain administrator privileges. User interaction is not required,” Microsoft says.
The tech giant flagged the security defect as publicly disclosed and believes that threat actors are likely to start exploiting it in attacks.
CVE-2026-72971, a link following in the Windows Container Isolation FS Filter Driver (unionfs.sys) that could lead to local tampering, was also flagged as publicly disclosed, but Microsoft believes it is unlikely to be exploited in the wild.
Other flaws that defenders should pay attention to include CVE-2026-62878, CVE-2026-62893, CVE-2026-62815, and CVE-2026-59124, which are remote code execution (RCE) bugs in Windows DNS server, Windows Deployment Services TFTP server, Microsoft QUIC, and Microsoft HPC Pack, as well as CVE-2026-62911, an EoP in Exchange Server, ZDI’s Dustin Childs notes.
In total, Microsoft’s August 2026 security updates resolve 236 vulnerabilities in Windows, 98 in Office, 98 in Office 2016, 30 in SharePoint Server, 26 in Developer Tools, 17 in Azure, 7 in Exchange Server, 1 in Defender, and 6 in other products.
The updates also include fixes for two non-Microsoft CVEs, namely a spoofing bug (CVE-2026-6726) and an information disclosure issue (CVE-2026-6727) in the TPM 2.0 reference implementation.
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