Last week, Apple released macOS Catalina 10.15.3 and appears to have patched the bug that could read messages from encrypted emails.
The bug was discovered by IT expert Bob Gendler and a longtime Mac fan in July, and months before he publicly announced it, but Apple did not take any action to resolve the issue. He also released details of the bug.
At the time, Apple announced that it would patch the reported bug with a software update in the future, and it now appears that the California company is keeping its promise after several months.
It's not bad here to point out that this bug probably affected a small population of users as the unencrypted portions of the emails were very limited in the macOS database and could only be viewed under certain circumstances.
The patch didn't mention the patch in the notes released with the .macOS Catalina 10.15.3 software update, but the comments Apple provided along with Catalina 5.1.1 beta say that the encrypted emails are now in Spotlight searches are not displayed. This means that Apple may have changed the way it lists Apple's encrypted emails to avoid bugs like what Gendler reported.
Gendler found in his tests that encrypted emails would no longer be included in the previous database file. He also noted that the AppleCare support team also contacted him directly to inform him of the software patch.Source