Why this month's Microsoft patch release is a doozy

Microsoft’s patch for September is a doozy, with a record number of roughly 972 vulnerabilities fixed and 112 of them meeting the high critical-severity threshold.

It was only two months ago that Microsoft patched a then-record 570 vulnerabilities. Then, last month, Microsoft patched some 620 of them. Google and other companies have also published record numbers of vulnerabilities in recent months. Two weeks ago, OpenAI, Anthropic, Amazon Web Services, Google, Microsoft, and 100 companies and organizations published an open letter warning of a narrowing window for patching vulnerabilities ahead of an expected tsunami of AI-enabled attacks that actively exploit them first. The industry is taking the threat seriously by pumping out unprecedented numbers of patches in their software.

Welcome to the new normal

Dustin Childs, a researcher at the Zero Day Initiative, calls the spikes the “new normal” and also cautions that despite them, the damage that’s likely to result from AI-assisted attacks could eventually be substantial.

“On the one hand, congrats to the security gnomes at Microsoft for being able to patch bugs at this rate,” Childs wrote Tuesday. “On the other hand, AI-assisted vulnerability discovery shows no signs of slowing down. However, we have not seen a correlating spike in active exploits—yet.”

Counting the precise number of vulnerabilities fixed in a monthly patch release for Microsoft is never an exact science. In some cases, the bugs were previously addressed or affected non-Microsoft products. By Childs’s count, Tuesday’s release patches 972 vulnerabilities, and 997 when counting the porting of fixes for the Chromium browser incorporated into Edge. Of the new vulnerabilities, 112 of them are rated critical, with the remainder carrying the important designation. Already this year, Microsoft has fixed 2,760 vulnerabilities, more than double the number from last year. At this rate, Microsoft will complete the year having fixed more bugs than all of 2023, 2024, and 2025 combined.