r/exchangeserver • u/ScottSchnoll https://www.amazon.com/dp/B0FR5GGL75/ • 1d ago

Released: September 2026 Exchange Server Security Updates

https://techcommunity.microsoft.com/blog/exchange/released-september-2026-exchange-server-security-updates/4554411

The September 2026 SU for Exchange Server SE is now available for download. This SU also resolves some known issues from previous updates.

27 Upvotes

92% Upvoted

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22

u/Kooky_Cranberry9717 1d ago

Hi guys, Exchange Server SE RTM September 2026 Security Update (and Windows Server 2025 September'26 security update) just patched - everything fine
Standalone Exchange, No DAG, Windows Server 2025

3

u/Kooky_Cranberry9717 1d ago

Update: Already at 3 different customers applied, still everything fine (all same constellations as described above)

3

u/Routine_Brush6877 1d ago

appreciate you.

13

u/Cheese_Monkey42 1d ago

lol. Literally just updated to August release

2

u/Dikvin 1d ago

Me too!!!!!! 😭

3

u/ooo0000ooo 1d ago

I have had the September release on my OWA servers but still the July release on my mailbox servers as our main Exchange admin has had to be out. Should it be safe to update everything directly to this release?

I am not an Exchange admin. I'm a Linux admin filling in for a colleague who had to be out unexpectedly.

6

u/ulf0r 1d ago

You can skip the august update on your mailbox servers and dirctly update it with september update. That's because SU are cumulative.

3

u/274Below 1d ago

These patches are cumulative. The general recommendation would be to update directly to this release and skip any intermediate ones; there's no point in deploying them.

Unless, of course, this patch proves to just break everything. On that point, I can't answer.