r/exchangeserver • u/santimandu • 14h 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

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13

u/rusty6713 14h ago

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

6

u/MortadellaKing 12h ago edited 9h 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 14h ago

Beat me to it!

2

u/fadinizjr 11h 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 13h 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 10h 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 10h 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 10h 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Me with my 2 mailboxes still on my ex2016 I'm struggling to migrate to 365 (no internet access to my way out of date exchange server)..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!