Sonarr randomly deleted a huge amount of shows from drive

Sonarr version (exact version): 3.0.7.1477
Mono version (if Sonarr is not running on Windows): 5.20.1.34
OS: Synology
Debug logs: https://hastebin.com/ukepavosot.yaml
Description of issue:

I noticed my Plex was not displaying a bunch of TV shows this evening so I went to look at the drive and a ton of shows were missing, only 16 shows left on my drive. All shows are in the same root folder so not sure why some shows were deleted and not others. Looking at the logs I can see around 10am today (8/2) the system ran a RSS Sync and completed. After that I see the RecycleBinProvider attempting to send a tv show folder to the recycling bin but since recycling bin is not configured it says it is deleting permanently. It does this over and over with a bunch of shows. I can’t tell why it’s doing this. Been running Sonarr for years and never had any issues.

Right now I will post the standard log and change it to debug in case it happens again and then I can post an updated log.

Sonarr does not do anything in it’s own.

Presumably you had sonarr opened up to the internet via port forward and didn’t put any authentication on sonarr

I had the same experience. The log showed Sonarr did a sync and then promptly deleted all the shows it was managing and deleted the video files. I didn’t have the recycle bin enabled. (I do now!) No, I don’t have it exposed to the Internet so I don’t think that was the attack vector - assuming this was an attack. I don’t think it was.

All the shows in Sonarr were also gone; it looked like a new install. I restored one of the database backups which brought back the shows, but I had to download everything again.

Sonarr’s worked great for years. This is really strange.
Version: 3.0.8.1507
.net Version: 4.8.0

an RSS sync has nothing to do with deleting entire series

again, there is no code in sonarr that has it magically delete series on its own. Only a human can trigger that via the UI or API