CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCVE-2021-21404
High (7.5) in syncthing syncthing. EPSS 2.0% chance of exploitation in the next 30 days. Fixed in github.com/syncthing/syncthing 1.15.0.
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.
Severity
- EPSS
- 2.0% chance of exploitation in the next 30 days; higher than 80% of CVEs (scores of 2026-10-31)
- CWE
- CWE-20
- Published
- Modified
- Record from
- the NVD, synced
Affected
- syncthing:syncthing
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-x462-89pf-6r5h | Go | github.com/syncthing/syncthing | <1.15.0 | 1.15.0 |
| GO-2022-0888 | Go | github.com/syncthing/syncthing | <1.15.0 | 1.15.0 |
References
- https://github.com/syncthing/syncthing/commit/fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97
- https://github.com/syncthing/syncthing/releases/tag/v1.15.0
- https://github.com/syncthing/syncthing/security/advisories/GHSA-x462-89pf-6r5h
- https://pkg.go.dev/github.com/syncthing/syncthing
- https://github.com/syncthing/syncthing/commit/fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97