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.
Advisories
Source ID Title
EUVD EUVD EUVD-2021-1226 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.
Github GHSA Github GHSA GHSA-x462-89pf-6r5h Crash due to malformed relay protocol message
Fixes

Solution

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Workaround

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2024-08-03T18:09:16.158Z

Reserved: 2020-12-22T00:00:00

Link: CVE-2021-21404

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2021-04-06T20:15:13.490

Modified: 2024-11-21T05:48:17.280

Link: CVE-2021-21404

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses