Patch Tuesday brought a record 1,411 fixes. One Windows flaw was already under attack.
By Lior AharonovFounder, 7IT Solutions ·
Microsoft's October 2026 Patch Tuesday on 13 October fixed 1,411 flaws, 70 of them critical, and three zero-days, per BleepingComputer. CVE-2026-96951, a Windows Shell bypass of Mark of the Web, is actively exploited. The other two zero-days were publicly disclosed: CVE-2026-108398 in .NET Framework and CVE-2026-92707 in MessagePack-CSharp.
Mark of the Web is the flag that makes Windows warn before a downloaded file runs. A bypass means the invoice attachment or the build tool from a download page can skip that warning. Developer laptops download files all day.
Install the October Windows updates on developer laptops and build machines first, since they open the most downloaded files. Then test your .NET apps that use MessagePack-CSharp against the update.
1,411 fixes is too many to read and one is too many to skip. Start with the one attackers already use.
Lior Aharonov · my takeSources
Researched with AI tools; every fact is checked against the linked sources.