{"id":"CVE-2021-21404","details":"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.","aliases":["BIT-syncthing-2021-21404","GHSA-x462-89pf-6r5h","GO-2022-0888"],"modified":"2026-07-09T10:21:17.295396Z","published":"2021-04-06T20:15:13.490Z","related":["openSUSE-SU-2021:0688-1","openSUSE-SU-2021:0713-1","openSUSE-SU-2024:11417-1"],"references":[{"type":"ADVISORY","url":"https://github.com/syncthing/syncthing/releases/tag/v1.15.0"},{"type":"ADVISORY","url":"https://github.com/syncthing/syncthing/security/advisories/GHSA-x462-89pf-6r5h"},{"type":"ADVISORY","url":"https://pkg.go.dev/github.com/syncthing/syncthing"},{"type":"FIX","url":"https://github.com/syncthing/syncthing/commit/fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/syncthing/syncthing","events":[{"introduced":"0"},{"fixed":"fb4fdaf4c0a79c22cad000c42ac1394e3ccb6a97"}],"database_specific":{"cpe":"cpe:2.3:a:syncthing:syncthing:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"fixed":"1.15.0"}],"source":["CPE_RANGE","REFERENCES"]}}],"versions":["v1.15.0-rc.6","v1.15.0-rc.5","v1.15.0-rc.4","v1.15.0-rc.3","v1.15.0-rc.2","v1.15.0-rc.1","v1.14.0-rc.1","v1.13.1","v1.13.0-rc.1","v1.13.0","v1.12.1-rc.1","v1.12.1","v1.12.0-rc.1","v1.11.0-rc.3","v1.11.0","v1.11.0-rc.2","v1.11.0-rc.1","v1.10.0-rc.3","v1.10.0","v1.10.0-rc.2","v1.10.0-rc.1","v1.9.0-rc.4","v1.9.0-rc.3","v1.9.0-rc.2","v1.9.0-rc.1","v1.8.0-rc.2","v1.8.0-rc.1","v1.7.0-rc.1","v1.7.0","v1.6.0-rc.1","v1.5.0-rc.1","v1.4.1-rc.1","v1.4.0-rc.5","v1.4.0-rc.4","v1.4.0-rc.3","v1.4.0-rc.2","v1.4.0-rc.1","v1.3.4-rc.1","v1.3.4","v1.3.3-rc.1","v1.3.3","v1.3.2-rc.1","v1.3.1-rc.2","v1.3.1-rc.1","v1.3.1","v1.3.0-rc.1","v1.2.2-rc.3","v1.2.2","v1.2.2-rc.2","v1.2.2-rc.1","v1.0.1-rc.2","v1.0.1","v1.2.1-rc.4","v1.2.1-rc.3","v1.2.1-rc.2","v1.2.1-rc.1","v1.2.0-rc.3","v1.2.0-rc.2","v1.2.0-rc.1","v1.1.4-rc.1","v1.1.4","v1.1.2-rc.1","v1.1.1-rc.1","v1.1.0-rc.1","v1.0.1-rc.1","v0.14.55-rc.2","v0.14.55-rc.1","v0.14.53-rc.1","v0.14.53","v0.14.52-rc.3","v0.14.52","v0.14.52-rc.1","v0.14.51-rc.3","v0.14.51-rc.2","v0.14.51-rc.1","v0.14.50-rc.1","v0.14.49-rc.4","v0.14.49","v0.14.49-rc.2","v0.14.49-rc.1","v0.14.48-rc.3","v0.14.48-rc.2","v0.14.48-rc.1","v0.14.47-rc.1","v0.14.46-rc.1","v0.14.45-rc.3","v0.14.45","v0.14.45-rc.2","v0.14.45-rc.1","v0.14.44-rc.2","v0.14.44-rc.1","v0.14.43-rc.1","v0.14.43","v0.14.42-rc.1","v0.14.42","v0.14.41-rc.2","v0.14.41-rc.1","v0.14.40-rc.1","v0.14.39-rc.1","v0.14.39","v0.14.38-rc.1","v0.14.38","v0.14.37-rc.3","v0.14.37","v0.14.37-rc.2","v0.14.37-rc.1","v0.14.36","v0.14.35","v0.14.34-rc.1","v0.14.33-rc.1","v0.14.33","v0.14.32-rc.2","v0.14.32","v0.14.32-rc.1","v0.14.31-rc.1","v0.14.31","v0.14.30-rc.1","v0.14.30","v0.14.29-rc.1","v0.14.29","v0.14.28-rc.1","v0.14.27-rc.2","v0.14.27-rc.1","v0.14.26-rc.1","v0.14.26","v0.14.25-rc.2","v0.14.25","v0.14.25-rc.1","v0.14.24-rc.1","v0.14.24","v0.14.22","v0.14.22-rc.1","v0.14.21","v0.14.20","v0.14.19","v0.14.18","v0.14.17","v0.14.14","v0.14.13","v0.14.12","v0.14.11","v0.14.10","v0.14.9","v0.14.8","v0.14.7","v0.14.6","v0.14.5","v0.14.4","v0.14.3","v0.14.2","v0.14.1","v0.14.0-rc.1","v0.14.0","v0.14.0-beta.1","v0.14.0-beta.0","v0.13.10","v0.13.9","v0.13.8","v0.13.7","v0.13.6","v0.13.5","v0.13.4","v0.13.3","v0.13.2","v0.13.1","v0.13.0","v0.13.0-beta.4","v0.13.0-beta.3","v0.13.0-beta.2","v0.13.0-beta.1","v0.13.0-beta.0","v0.12.11","v0.12.10","v0.12.9","v0.12.8","v0.12.7","v0.12.6","v0.12.5","v0.12.4","v0.12.3","v0.12.2","v0.12.1","v0.12.0","v0.12.0-rc6","v0.12.0-rc5","v0.12.0-rc4","v0.12.0-rc3","v0.12.0-rc2","v0.12.0-rc1","v0.12.0-beta4","v0.12.0-beta3","v0.12.0-beta2","v0.12.0-beta1","v0.12.0-beta0","v0.11.20","v0.11.18","v0.11.17","v0.11.16","v0.11.15","v0.11.14","v0.11.13","v0.11.12","v0.11.11","v0.11.10","v0.11.9","v0.11.8","v0.11.7","v0.11.6","v0.11.5","v0.11.4","v0.11.3","v0.11.2","v0.11.1","v0.11.0","v0.11.0-rc1","v0.11.0-rc0","v0.11.0-beta6","v0.11.0-beta5","v0.11.0-beta4","v0.11.0-beta3","v0.11.0-beta2","v0.11.0-beta1","v0.11.0-beta0","v0.10.27","v0.10.26","v0.10.25","v0.10.24","v0.10.23","v0.10.22","v0.10.21","v0.10.20","v0.10.19","v0.10.18","v0.10.17","v0.10.16","v0.10.15","v0.10.14","v0.10.13","v0.10.12","v0.10.11","v0.10.10","v0.10.9","v0.10.8","v0.10.7","v0.10.6","v0.10.5","v0.10.4","v0.10.3","v0.10.2","v0.10.1","v0.10.0","v0.10.0-beta1","v0.9.18","v0.9.17","v0.9.16","v0.9.15","v0.9.14","v0.9.13","v0.9.11","v0.9.10","v0.9.9","v0.9.8","v0.9.7","v0.9.6","v0.9.5","v0.9.2","v0.9.1","v0.9.0","v0.9.0-beta9","v0.9.0-beta8","v0.9.0-beta7","v0.9.0-beta6","v0.9.0-beta5","v0.9.0-beta4","v0.9.0-beta3","v0.9.0-beta2","v0.9.0-beta1","v0.8.16","v0.8.15","v0.8.14","v0.8.13","v0.8.12","v0.8.11","v0.8.10","v0.8.9","v0.8.8","v0.8.7","v0.8.6","v0.8.5","v0.8.4","v0.8.3","v0.8.2","v0.8.1","v0.8.0","v0.7.2","v0.7.1","v0.7.0","v0.6.6","v0.6.5","v0.6.4","v0.6.3","v0.6.2","v0.6.0","v0.5.4","v0.5.3","v0.5.2","v0.5.1","v0.5.0","v0.4.3","v0.4.2","v0.4.1","v0.4.0","v0.3.3","v0.3.2","v0.3.1","v0.3.0","v0.2.2","v0.2.1","v0.2","v0.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-o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