Patch Tuesday

October 2026 for Microsoft admins: what changed on the 1st, and what ends on Patch Tuesday

Patch Tuesday was on 13 October, and this one was more than a batch of fixes. Several products got their last update on the same day, three things had already changed on 1 October, and a Secure Boot certificate expires six days later. Here is the month as a list, with what to check for each.

September 2026 Patch Tuesday broke Excel: the case for ring-based deployment

September’s Patch Tuesday was the biggest Microsoft has ever shipped, and one of the updates in it broke copy and paste in Excel. Together they make a good argument for something small IT departments often skip: letting a few people get the updates first.

What shipped on 8 September 2026

A record count, however you count it

How big depends on who you ask. BleepingComputer counted 966 vulnerabilities [1], Tenable 964 [2], the Zero Day Initiative 972 new Microsoft CVEs [3] and SecurityWeek 974 [4]. When I first noted the idea for this post I wrote down 973, which is roughly what you get from reading enough headlines.