Microsoft's August 2026 Patch Tuesday fixes ~400 flaws, three zero-days
Monthly security update patches a Windows kernel flaw already under active attack alongside new Windows 11 features.
Conversation activity · last 7 hours peak 6/15m
Summary, timeline and people extracted by Claude from 9 items across 4 sources · 47m ago. Quotes are verbatim.
Microsoft released its August 2026 Patch Tuesday updates, addressing roughly 400 vulnerabilities (counts range from 398 to 421 depending on the source) including three zero-day flaws — one of which, a Windows kernel bug, is already being exploited by attackers. The same rollout, delivered via KB5121000 and KB5121003, also adds new Windows 11 features such as precision touchpad gesture controls and Windows Hello support for peripheral fingerprint sensors.
- Microsoft's August 2026 Patch Tuesday fixes roughly 400 vulnerabilities, with counts varying by source (398 per Zero Day Initiative, 400 per BleepingComputer, 421 per Undercodenews).
- Three zero-day vulnerabilities were addressed, including one Windows kernel flaw already being actively exploited to execute code at system level, plus two publicly disclosed zero-days.
- 62 of the fixed vulnerabilities are rated 'Critical' according to the Zero Day Initiative.
- The same update (KB5121000/KB5121003) also introduces new Windows 11 features: precision touchpad gesture controls, Windows Hello support for peripheral fingerprint sensors, and Widgets/Voice Access improvements.
How it unfolded
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A security commentary site described the patch batch as urgent, citing a total of 421 CVEs and a Windows kernel zero-day already under exploitation, urging administrators and enterprise defenders to act.
“Microsoft's August 2026 Patch Tuesday Is a Wake-Up Call: 421 CVEs and a Windows Kernel Zero-Day Already Exploited”
Undercodenews · Mastodon ↗ -
Thurrott outlined new touchpad gestures, Windows Hello fingerprint-sensor support, and Widgets changes, and cited the Zero Day Initiative's count of 398 CVEs fixed, 62 rated Critical.
“The security experts at the Zero Day Initiative mentioned a total of 398 CVEs (Common Vulnerabilities and Exposures) that have been addressed this month, with 62 of them rated 'Critical', and just one 'Important' flaw that's being actively…”
Zero Day Initiative (via Thurrott) · Google News ↗ -
BleepingComputer reported the update addresses about 400 vulnerabilities, including one actively exploited zero-day and two publicly disclosed zero-days.
“Today is Microsoft's August 2026 Patch Tuesday, and with it comes security updates for a massive 400 flaws, including one actively exploited and two publicly disclosed zero-day vulnerabilities.”
BleepingComputer · Mastodon ↗ -
Microsoft released KB5121000 (Windows 11 26H1) and KB5121003 (Windows 11 25H2/24H2), bundling security fixes with new OS features.
What people are saying verbatim
“Today is Microsoft's August 2026 Patch Tuesday, and with it comes security updates for a massive 400 flaws, including one actively exploited and two publicly disclosed zero-day vulnerabilities.”
BleepingComputer, Security news outlet · Mastodon ↗ · Aug 10
“The August 2026 Patch Tuesday updates for Windows 11 bring new gesture controls on PCs with precision touchpads, support for Windows Hello authentication on peripheral fingerprint sensors, and more”
laurentgiret@mastodon.social, Thurrott senior news editor · Mastodon ↗ · Aug 10
“The security experts at the Zero Day Initiative mentioned a total of 398 CVEs (Common Vulnerabilities and Exposures) that have been addressed this month, with 62 of them rated 'Critical', and just one 'Important' flaw that's being actively used by attackers to execute code at system level.”
Thurrott (citing Zero Day Initiative), Tech news outlet · Thurrott.com · Aug 10
“Microsoft's August 2026 Patch Tuesday Is a Wake-Up Call: 421 CVEs and a Windows Kernel Zero-Day Already Exploited”
undercodenews@mastodon.social, Security commentary site · Mastodon ↗ · Aug 10
Voices from the web unedited
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The August 2026 Patch Tuesday updates for Windows 11 bring new gesture controls on PCs with precision touchpads, support for Windows Hello authentication on peripheral fingerprint sensors, and more https://www. thurrott.com/windows/340326/mi crosoft-releases-august-2026-patch-tuesday-updates # windows11 # patchtuesday # technology
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Microsoft’s August 2026 Patch Tuesday Is a Wake-Up Call: 421 CVEs and a Windows Kernel Zero-Day Already Exploited + Video A Massive Security Update Arrives Under Pressure Microsoft’s August 2026 Patch Tuesday has landed with a security update that should immediately capture the attention of Windows administrators, security teams, and enterprise…
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Today is Microsoft's August 2026 Patch Tuesday, and with it comes security updates for a massive 400 flaws, including one actively exploited and two publicly disclosed zero-day vulnerabilities. https://www. bleepingcomputer.com/news/micr osoft/microsoft-august-2026-patch-tuesday-fixes-400-flaws-3-zero-days/