CVE-2021-21404 Information

Description

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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Reference

https://github.com/syncthing/syncthing/releases/tag/v1.15.0 https://github.com/syncthing/syncthing/commit/fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97 https://github.com/syncthing/syncthing/security/advisories/GHSA-x462-89pf-6r5h https://pkg.go.dev/github.com/syncthing/syncthing

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

7.5