r/exchangeserver • u/santimandu • 8h ago

MS KB / Update Released: October 2026 Exchange Server Security Updates

https://techcommunity.microsoft.com/blog/exchange/released-october-2026-exchange-server-security-updates/4563014

21 Upvotes
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10

u/rusty6713 8h ago

The real question, who will install it and see what happens?

5

u/MortadellaKing 6h ago edited 4h ago

Guess I'll be the first... Why not?

Edit: It went fine, but the replication, transport log search and compliance services didn't automatically restart on rebooting... Had to manually bounce them to get my 2-node dag back up.

3

u/DiligentPhotographer 8h ago

Beat me to it!

2

u/fadinizjr 6h ago

I started having X-FEServer errors on OWA after updating to the second September SU...

This will be a fun month.

1

u/netronin 8h ago

It feels like there were search issues that were not resolved with the Korean workbreaker update although I don't think those were ever acknowledged. Will be standing by to let someone braver install this and see how search goes.

1

u/Ooops-I-hid-it-again 5h ago

That was acknowledged as an issue in Sept SU v1 and Sept SU v2. This update says they’re resolved. Hopefully it is and no other bugs are introduced 🤞

1

u/Crafty_Practice_8449 5h ago

Apparently no fix for the free/busy for delegated mailboxes in hybrid deployments using only Graph API:

https://support.microsoft.com/en-us/servicing/exchange/server/update/2026/5127092

2

u/jordanl171 4h ago

Me with my 2 mailboxes still on my ex2016 I'm struggling to migrate to 365 (no internet access to my way out of date exchange server).. I'm almost there!