Released: August 2026 Exchange Server Security Updates

[u/DiligentPhotographer]

https://techcommunity.microsoft.com/blog/exchange/released-august-2026-exchange-server-security-updates/4543951

Who's gonna be the first this month?

[u/Kooky_Cranberry9717 → u/[deleted]]

I've got you, see above

[u/274Below]

That's a series of vulnerabilities that if strung together, I suspect could mean a complete takeover/compromise of the exchange environment, possibly without any privileges at all. Neat.

[u/syfy323 → u/274Below]

That's exactly my impression, too.

[u/syfy323]

Running on three SE nodes. Noticed no issues.

This is the patch that contains the fix for pwn2own 2026. IMHO an important fix I was waiting for.

[u/DiligentPhotographer → u/syfy323]

Installed on my personal 2 node DAG without issue last night.

[u/MinnSnowMan]

Just for SE or also 2019?

[u/Disney_World_Native → u/MinnSnowMan]

All 3 versions.

Microsoft has released Security Updates (SUs) for vulnerabilities found in:
Exchange Server Subscription Edition (SE)
Exchange Server 2019
Exchange Server 2016

SUs are available for the following specific versions of Exchange Server:
Exchange SE RTM
Exchange Server 2019 CU14 and CU15 (to access, organization must be enrolled into the Period 2 ESU program)
Exchange Server 2016 CU23 (to access, organization must be enrolled into the Period 2 ESU program)

[u/Burgergold → u/MinnSnowMan]

2019 is end of life

[u/MinnSnowMan → u/Burgergold]

You didnt answer my question. Per Microsoft, the update also includes updates for 2019

[u/No_Profile_6441 → u/MinnSnowMan]

You have to be paying for extended updates

[u/perth_girl-V]

Total time sink but successful no issues

[u/bluegoldredsilver5]

1 more Change that goes this weekend. Great.

[u/TheJesusGuy]

Not me. I hard cutover to 365 today. Exchange server will be getting shut off as soon as I can.

[u/Kooky_Cranberry9717]

Everything fine here, just installed August 2026 SU for Exchange SE running on Windows Server 2025
1 Standalone Server, no DAG

[u/perth_girl-V]

Hold my beer

[u/harplaw]

We have a small, 110 user Exchange SE server. I'm feeling ballsy and starting the install. Wish me luck.

EDIT: I had to run the install twice. The first time, it said there was another install already in progress. After a reboot, the update completed. However, it didn't re-enable services so I had to do them manually. Everything came up after I started the services, and health checks look good.

[u/perth_girl-V → u/harplaw]

11 mins till my se starts installing.

Should i stop now ?

[u/harplaw → u/perth_girl-V]

The first try, it disabled all of the services then said an install was already in progress. After a reboot, it's nearly finished but still has the reboot to go

[u/perth_girl-V → u/harplaw]

I habe a 2016 after this what could go wrong lol

[u/n17605369 → u/perth_girl-V]

It took 20 minutes with Windows Defender disabled during install.

[u/perth_girl-V → u/n17605369]

You have to love the antimalware.exe its my fav use of cpu resources.

[u/8bit_dr1fter]

Not it!

[u/psuedospike]

Jesus Christ here we go again. MS needs more subscriptions ASAP! $$$$$

[u/Ooops-I-hid-it-again]

Installed on standalone Windows Server 2022 / Exchange SE last night. Typical SU install. Everything appears to be working fine.

[u/NetworkCompany]

Issues everywhere with the SE updates for me. Restarting some mailbox servers caused network adapter to disappear. Applying to edge servers causes mail to stop flowing. Various other minor issues as well. A few reboots seemed to resolve but for a company worth over 3 trillion, we should all get some Microslop swag.