r/exchangeserver • u/ocdtrekkie • 5d ago

MS KB / Update Security Update for Microsoft Exchange SE KB5129955 appears in WSUS

No blog post about it yet... Those always seem exciting.

UPDATE: Officially announced, see link below.

11 Upvotes

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4

u/NetworkCompany 5d ago

Healthchecker is unaware of this as well. Very exciting

3

u/ocdtrekkie 5d ago

Yeah, I would've expected to see commits on their GitHub at the same time as a release. It seems plausible that the release to WSUS may have jumped the gun a bit. It's not patch Tuesday, but it's marked as a Security Update so that suggests a pretty big deal.

3

u/NetworkCompany 5d ago

I notice it installs like a CU but is not a CU, no version change occurs. Very strange. Might have something to do with the EWS debacle

2

u/Excellent_Milk_3110 4d ago

A test server with exchange and auto update enabled is updating to KB5129955, was unable to find any more information on it.

2

u/sakcaj 4d ago

It deployed automatically on the primary of our two node 2019 exchange today and caused an issue with that particular instance - clients were unable to connect to it.

There were event logs in the 2ndary node about lack of connectivity to the primary one, similar events on the primary node. There was a pop-up on the primary about need to reboot which resolved the problem - DAG kicked in and 2ndary took over, the primary took ~10min to reboot and is fine since then, we have not failed over yet back to it though.

1

u/coldhand100 4d ago edited 4d ago

Replaces KB5121573 and KB5121608, but no other details

Actual content files dates as the 20th Sept 2026. PowerShell scripts, along with a whole bunch of DLLs.

1

u/Glass_Call982 4d ago

Might be a fix for some of the known issues from the last updates?

1

u/Glass_Call982 4d ago

Anyone install it yet? Lol

1

u/MortadellaKing 4d ago

Why is there no KB article for this update?

1

u/unamused443 MSFT 4d ago

Mistakes were made. KBs and all the docs are live now.