{"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-538355041\" 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-3033980824\" 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\/ml2u-226-watch-face-fuer-wearos-im-google-play-store\/\">\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\/10\/deal-3-150x150.png\" 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\">ML2U 226 Watch Face f\u00fcr WearOS im Google Play Store<\/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\">Gratis<\/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>1.39 \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\">-100%<\/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\t55\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\/star-citizen-twitch-drops-deko-fuer-den-hangar\/\">\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\/10\/source-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\">Star Citizen Twitch Drops \u2013 Deko f\u00fcr den Hangar<\/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\">Gratis<\/span>\n\t\t\t\t\t\t\t\t\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<\/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\t55\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\/moon-knight-digital-watch-face-fuer-wear-os-4\/\">\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\/deal-27-150x150.png\" 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\">MOON KNIGHT Digital Watch Face f\u00fcr Wear OS 4+<\/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\">Gratis<\/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>0.89 \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\">-100%<\/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\t55\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\/battlefield-6-code-fuer-spielerkartenhintergrund-und-titel\/\">\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\/10\/battlefield-6-how-to-redeem-codes-asset-code-9-2026_de-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\">Battlefield 6 \u2013 Code f\u00fcr Spielerkartenhintergrund und Titel<\/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\">Gratis<\/span>\n\t\t\t\t\t\t\t\t\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<\/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\t55\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\/train-sim-world-7-starter-pack-kostenlos-fuer-ps4-ps5-xbox-pc\/\">\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\/capsule_616x353-11-150x150.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\">Train Sim World 7: Starter Pack kostenlos f\u00fcr PS4, PS5, Xbox, PC<\/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\">Gratis<\/span>\n\t\t\t\t\t\t\t\t\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<\/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\t55\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-667953482\" 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":{"_affilinode_tracking":"","_affilinode_autolink_off":false,"_affilinode_rating":"","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":[430],"tags":[],"class_list":["post-1459","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-cybersecurity-en"],"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}]}}