Microsoft’s Record 1,400-Flaw Patch Tuesday at a Glance, Plus a Checklist for Small IT Teams
Microsoft’s October updates fix more than 1,400 vulnerabilities, a new monthly record, including one Windows flaw already used in attacks. Here are the key numbers and a practical order for getting them installed.
Microsoft’s October Patch Tuesday is the biggest it has ever shipped, and it lands on teams that were still digesting September’s record. Below are the facts in spec-sheet form, followed by a checklist for deciding what to do first.
The numbers come from Brian Krebs’ Patch Tuesday roundup at Krebs on Security, with the per-product breakdown and flaw details from The Hacker News.
The spec sheet
- Total: 1,413 vulnerabilities, per The Hacker News; Krebs reports “more than 1,400.” September’s previous record was nearly 1,000.
- By product: 1,102 in Windows, 134 in Office, 61 in Developer Tools, 36 in SharePoint Server and 22 in SQL Server.
- By type: more than 670 privilege escalation flaws, over 300 remote code execution flaws and about 250 information disclosure flaws.
- Critical: at least 78 rated critical, according to Krebs; The Hacker News puts it at over 70.
- Exploited now: CVE-2026-96951 (8.8), a Windows Shell command injection that bypasses Mark of the Web protections. A victim has to be tricked into opening a crafted file or link. CISA wants federal agencies patched by October 16.
- Publicly known before release: CVE-2026-108398 (8.8), a .NET Framework flaw that can bypass Windows Defender Application Control, and CVE-2026-92707 (5.3), a denial-of-service bug in MessagePack-CSharp.
- Worth a look: CVE-2026-21413 (9.8) in the Raw Image Extension, which can be triggered just by Windows generating a thumbnail or preview of a crafted RAW image.
- Year to date: more than 4,000 Microsoft CVEs, above the previous full-year record of 1,261 set in 2020, per Tenable’s Satnam Narang.
- New this month: Microsoft is grouping related flaws into “risk cohorts” to help prioritize, while saying each CVE should still be reviewed.
- Windows 10: Krebs notes Microsoft has quietly extended free security updates for Windows 10 until October 2027.
Why the number keeps climbing
Microsoft credits AI-assisted research for much of the volume. Dustin Childs of the Zero Day Initiative put it this way: AI “isn’t creating these bugs out of thin air; it’s just shortening the time between a vulnerability existing and someone noticing it.” His advice is to “patch what’s proven, prioritized, and public.” Fortra’s Tyler Reguly points out that only 26 Microsoft vulnerabilities have entered CISA’s Known Exploited Vulnerabilities catalog so far this year, a sensible place to start.
What this means for your company: the checklist
- Install the Windows cumulative update first. It carries the fix for the exploited Windows Shell flaw. Test on a few machines, then roll out within days, not weeks.
- Remind staff about unexpected files. The exploited bug needs someone to open a crafted file or link, so a short note this week is worth sending.
- Update the Raw Image Extension. It updates through the Microsoft Store, so confirm Store updates are not blocked on business machines.
- Patch servers next. Prioritize SharePoint Server, SQL Server and anything reachable from the internet.
- Check .NET and developer tools. Developer machines and build servers often fall outside normal patching.
- Confirm it actually landed. Use your management tool’s reports to find devices that failed or never checked in.
Need help keeping up with record-sized monthly patch releases? Reach out to Layer 7 Data Solutions to discuss how we’ve helped companies similar to yours.
About The Author
