Vulnerabilities > CVE-2021-21404 - Unspecified vulnerability in Syncthing
Summary
Syncthing is a continuous file synchronization program. In Syncthing before version 1.15.0, the relay server `strelaysrv` can be caused to crash and exit by sending a relay message with a negative length field. Similarly, Syncthing itself can crash for the same reason if given a malformed message from a malicious relay server when attempting to join the relay. Relay joins are essentially random (from a subset of low latency relays) and Syncthing will by default restart when crashing, at which point it's likely to pick another non-malicious relay. This flaw is fixed in version 1.15.0.
Vulnerable Configurations
References
- https://github.com/syncthing/syncthing/commit/fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97
- https://github.com/syncthing/syncthing/commit/fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97
- https://github.com/syncthing/syncthing/releases/tag/v1.15.0
- https://github.com/syncthing/syncthing/releases/tag/v1.15.0
- https://github.com/syncthing/syncthing/security/advisories/GHSA-x462-89pf-6r5h
- https://github.com/syncthing/syncthing/security/advisories/GHSA-x462-89pf-6r5h
- https://pkg.go.dev/github.com/syncthing/syncthing
- https://pkg.go.dev/github.com/syncthing/syncthing