{"id":1459,"date":"2026-08-12T10:00:00","date_gmt":"2026-08-12T10:00:00","guid":{"rendered":"https:\/\/netguide.io\/news\/2026\/08\/12\/microsoft-patch-tuesday-august-2026-421-flaws\/"},"modified":"2026-08-17T23:12:41","modified_gmt":"2026-08-17T23:12:41","slug":"microsoft-patch-tuesday-august-2026-421-flaws","status":"publish","type":"post","link":"https:\/\/netguide.io\/news\/en\/2026\/08\/12\/microsoft-patch-tuesday-august-2026-421-flaws\/","title":{"rendered":"Microsoft Patch Tuesday: 421 Flaws, One Zero-Day Active"},"content":{"rendered":"<div id=\"netgu-584075509\" class=\"netgu-before-content netgu-entity-placement\"><script async src=\"\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-6258556257245998\" crossorigin=\"anonymous\"><\/script><ins class=\"adsbygoogle\" style=\"display:block;\" data-ad-client=\"ca-pub-6258556257245998\" \ndata-ad-slot=\"3494115342\" \ndata-ad-format=\"auto\"><\/ins>\n<script> \n(adsbygoogle = window.adsbygoogle || []).push({}); \n<\/script>\n<\/div>\n<p class=\"wp-block-paragraph\"><strong>On August Patch Tuesday 2026, Microsoft released fixes for 421 security vulnerabilities \u2013 an unusually high number. Among them is an already actively exploited zero-day, plus several critical flaws that allow remote code execution. Users and administrators should update promptly.<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">The actively exploited zero-day<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Considered already under attack is CVE-2026-68820: a use-after-free flaw in the WinSock driver (<code>afd.sys<\/code>). Attackers used it to elevate their privileges on a system all the way to SYSTEM level \u2013 gaining full control.<\/p><div id=\"netgu-2968437512\" class=\"netgu-content netgu-entity-placement\"><aside class=\"deals-top deals-top--compact\">\n\n\t\t\t<h3 class=\"deals-top__title\">Top-Deals<\/h3>\n\t\n\t\t\t<ul class=\"deals-top__list\">\n\t\t\t\t\t\t\t<li class=\"deals-top__item\">\n\t\t\t\t\t<a class=\"deals-top__link\" href=\"https:\/\/netguide.io\/deals\/de\/deals\/orico-bluetooth-lautsprecher-bg01-farbenfroh-fuer-1609e\/\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<img class=\"deals-top__image\" src=\"https:\/\/netguide.io\/news\/wp-content\/uploads\/sites\/15\/2026\/09\/b0gyqztlt6-150x150.jpg\" alt=\"\" width=\"52\" height=\"52\" loading=\"lazy\" \/>\n\t\t\t\t\t\t\n\t\t\t\t\t\t<span class=\"deals-top__body\">\n\t\t\t\t\t\t\t<span class=\"deals-top__name\">ORICO Bluetooth Lautsprecher BG01 \u2013 Farbenfroh f\u00fcr 16,09\u20ac<\/span>\n\n\t\t\t\t\t\t\t<span class=\"deals-top__meta\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"deals-top__price\">16.09 \u20ac<\/span>\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<s>40.00 \u20ac<\/s>\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"deals-discount\">-60%<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<\/span>\n\n\t\t\t\t\t\t<span class=\"deals-top__temperature\">\n\t\t\t\t\t\t\t40\u00b0\n\t\t\t\t\t\t<\/span>\n\t\t\t\t\t<\/a>\n\t\t\t\t<\/li>\n\t\t\t\t\t\t\t<li class=\"deals-top__item\">\n\t\t\t\t\t<a class=\"deals-top__link\" href=\"https:\/\/netguide.io\/deals\/de\/deals\/shoot-em-up-clive-owen\/\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<img class=\"deals-top__image\" src=\"https:\/\/netguide.io\/news\/wp-content\/uploads\/sites\/15\/2026\/09\/1200x675-1-150x150.jpg\" alt=\"\" width=\"52\" height=\"52\" loading=\"lazy\" \/>\n\t\t\t\t\t\t\n\t\t\t\t\t\t<span class=\"deals-top__body\">\n\t\t\t\t\t\t\t<span class=\"deals-top__name\">Shoot \u2018Em Up | Clive Owen<\/span>\n\n\t\t\t\t\t\t\t<span class=\"deals-top__meta\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"deals-top__price\">3.99 \u20ac<\/span>\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<s>9.99 \u20ac<\/s>\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"deals-discount\">-60%<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<\/span>\n\n\t\t\t\t\t\t<span class=\"deals-top__temperature\">\n\t\t\t\t\t\t\t38\u00b0\n\t\t\t\t\t\t<\/span>\n\t\t\t\t\t<\/a>\n\t\t\t\t<\/li>\n\t\t\t\t\t\t\t<li class=\"deals-top__item\">\n\t\t\t\t\t<a class=\"deals-top__link\" href=\"https:\/\/netguide.io\/deals\/de\/deals\/multifunktionsgeraet-fuer-den-alltag\/\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<img class=\"deals-top__image\" src=\"https:\/\/netguide.io\/news\/wp-content\/uploads\/sites\/15\/2026\/09\/Daily-Dealz-150x150.jpg\" alt=\"\" width=\"52\" height=\"52\" loading=\"lazy\" \/>\n\t\t\t\t\t\t\n\t\t\t\t\t\t<span class=\"deals-top__body\">\n\t\t\t\t\t\t\t<span class=\"deals-top__name\">Multifunktionsger\u00e4t f\u00fcr den Alltag<\/span>\n\n\t\t\t\t\t\t\t<span class=\"deals-top__meta\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"deals-top__price\">4.90 \u20ac<\/span>\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<s>79.99 \u20ac<\/s>\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"deals-discount\">-94%<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<\/span>\n\n\t\t\t\t\t\t<span class=\"deals-top__temperature\">\n\t\t\t\t\t\t\t32\u00b0\n\t\t\t\t\t\t<\/span>\n\t\t\t\t\t<\/a>\n\t\t\t\t<\/li>\n\t\t\t\t\t\t\t<li class=\"deals-top__item\">\n\t\t\t\t\t<a class=\"deals-top__link\" href=\"https:\/\/netguide.io\/deals\/de\/deals\/the-elder-scrolls-v-skyrim-anniversary-edition-fuer-nintendo-switch\/\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<img class=\"deals-top__image\" src=\"https:\/\/netguide.io\/news\/wp-content\/uploads\/sites\/15\/2026\/09\/2834768_1-150x150.webp\" alt=\"\" width=\"52\" height=\"52\" loading=\"lazy\" \/>\n\t\t\t\t\t\t\n\t\t\t\t\t\t<span class=\"deals-top__body\">\n\t\t\t\t\t\t\t<span class=\"deals-top__name\">The Elder Scrolls V: Skyrim Anniversary Edition f\u00fcr Nintendo Switch<\/span>\n\n\t\t\t\t\t\t\t<span class=\"deals-top__meta\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"deals-top__price\">20.00 \u20ac<\/span>\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<s>37.00 \u20ac<\/s>\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"deals-discount\">-46%<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<\/span>\n\n\t\t\t\t\t\t<span class=\"deals-top__temperature\">\n\t\t\t\t\t\t\t27\u00b0\n\t\t\t\t\t\t<\/span>\n\t\t\t\t\t<\/a>\n\t\t\t\t<\/li>\n\t\t\t\t\t\t\t<li class=\"deals-top__item\">\n\t\t\t\t\t<a class=\"deals-top__link\" href=\"https:\/\/netguide.io\/deals\/de\/deals\/severin-toaster-101-cool-touch-wasserkocher-und-doppel-langschlitztoaster\/\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<img class=\"deals-top__image\" src=\"https:\/\/netguide.io\/news\/wp-content\/uploads\/sites\/15\/2026\/09\/2834960_1-150x150.webp\" alt=\"\" width=\"52\" height=\"52\" loading=\"lazy\" \/>\n\t\t\t\t\t\t\n\t\t\t\t\t\t<span class=\"deals-top__body\">\n\t\t\t\t\t\t\t<span class=\"deals-top__name\">Severin Toaster 101\u00b0 \u2013 Cool-Touch Wasserkocher und Doppel-Langschlitztoaster<\/span>\n\n\t\t\t\t\t\t\t<span class=\"deals-top__meta\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"deals-top__price\">17.99 \u20ac<\/span>\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<s>39.99 \u20ac<\/s>\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"deals-discount\">-55%<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t<\/span>\n\n\t\t\t\t\t\t<span class=\"deals-top__temperature\">\n\t\t\t\t\t\t\t30\u00b0\n\t\t\t\t\t\t<\/span>\n\t\t\t\t\t<\/a>\n\t\t\t\t<\/li>\n\t\t\t\t\t<\/ul>\n\n\t\t\t\t\t<p class=\"deals-top__more\">\n\t\t\t\t<a href=\"https:\/\/netguide.io\/deals\/\">Alle Deals ansehen \u2192<\/a>\n\t\t\t<\/p>\n\t\t\t<\/aside>\n<\/div>\n\n\n\n<h3 class=\"wp-block-heading\">Critical remote attacks without user interaction<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Microsoft QUIC (CVE-2026-62815):<\/strong> a critical RCE flaw with a CVSS score of 9.8. An unauthenticated attacker can execute code remotely \u2013 with no action from the victim.<\/li>\n\n\n\n<li><strong>Windows DNS Server:<\/strong> several critical RCE flaws (including CVE-2026-62878 and CVE-2026-62817) exploitable via crafted packets and without user interaction.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The DNS and QUIC fixes are especially urgent for server operators, since they can be exploited without authentication and without any user action. On home PCs, Windows Update usually installs the patches automatically \u2013 but a manual check does no harm.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Sources: <a href=\"https:\/\/www.securityweek.com\/august-2026-patch-tuesday-microsoft-fixes-421-cves-one-exploited-zero-day\/\" target=\"_blank\" rel=\"noopener\">SecurityWeek<\/a>, <a href=\"https:\/\/www.zerodayinitiative.com\/blog\/2026\/8\/11\/the-august-2026-security-update-review\" target=\"_blank\" rel=\"noopener\">Zero Day Initiative<\/a>.<\/em><\/p>\n<div id=\"netgu-3280679862\" class=\"netgu-after-content netgu-entity-placement\"><script async src=\"\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-6258556257245998\" crossorigin=\"anonymous\"><\/script><ins class=\"adsbygoogle\" style=\"display:block;\" data-ad-client=\"ca-pub-6258556257245998\" \ndata-ad-slot=\"4559785002\" \ndata-ad-format=\"auto\"><\/ins>\n<script> \n(adsbygoogle = window.adsbygoogle || []).push({}); \n<\/script>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>On August Patch Tuesday, Microsoft fixes 421 vulnerabilities \u2013 including an actively exploited zero-day and critical RCE flaws in QUIC and the DNS Server.<\/p>\n","protected":false},"author":1,"featured_media":1549,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[],"tags":[],"class_list":["post-1459","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry"],"brizy_media":[],"_links":{"self":[{"href":"https:\/\/netguide.io\/news\/wp-json\/wp\/v2\/posts\/1459","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/netguide.io\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/netguide.io\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/netguide.io\/news\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/netguide.io\/news\/wp-json\/wp\/v2\/comments?post=1459"}],"version-history":[{"count":1,"href":"https:\/\/netguide.io\/news\/wp-json\/wp\/v2\/posts\/1459\/revisions"}],"predecessor-version":[{"id":1551,"href":"https:\/\/netguide.io\/news\/wp-json\/wp\/v2\/posts\/1459\/revisions\/1551"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/netguide.io\/news\/wp-json\/wp\/v2\/media\/1549"}],"wp:attachment":[{"href":"https:\/\/netguide.io\/news\/wp-json\/wp\/v2\/media?parent=1459"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/netguide.io\/news\/wp-json\/wp\/v2\/categories?post=1459"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/netguide.io\/news\/wp-json\/wp\/v2\/tags?post=1459"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}