Microsoft patches Y2K-like bug that borked on-prem Exchange Server
Happy New Year. Welcome back! Now apply this patch – which Microsoft warns isn't easy – if you want email to work

Microsoft has kicked off 2022 by issuing a patch for Exchange Server 2016 and 2019, which both possessed a “latent date issue” that saw emails queued up instead of being dispatched to inboxes.

“The problem relates to a date check failure with the change of the new year,” states a January 1st post to the Exchange Blog.

Exchange’s malware scanning engine is the source of the problem, as Exchange checks the version of that software and then tries to write the date into a variable. But that variable’s maximum value is 2,147,483,647 and the value Exchange tries to write - 2,201,010,001, to reflect the date of January 1st, 2022, at midnight – exceeds the variable’s maximum threshold.

The malware engine therefore crashes when it reads the variable.

Deprived of its malware-scanner – an important element of a mail server - Exchange queues mail instead of sending it.
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