The Computer Emergency Response Team of Ukraine (CERT-UA) reports about a new campaign dubbed "SickSync," launched by the UAC-0020 (Vermin) hacking group in attacks on the Ukrainian defense forces.
Correct me if I'm wrong, but this doesn't look like this has anything to do with Syncthing vulnerabilities. Instead it looks like a hack that uses a preconfigured Syncthing installation to transfer sensitive data. Disturbing nonetheless.
It's a convenient file transfer/sync tool. Copying data has to happen somehow, I'm not surprised someone thought to use syncthing for that purpose >.<, since it can do that. But its not really different than any other tool here.