Upstream information

CVE-2021-21404 at MITRE

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.

SUSE information

Overall state of this security issue: Resolved

This issue is currently rated as having important severity.

CVSS v2 Scores
CVSS detail National Vulnerability Database
Base Score 5
Vector AV:N/AC:L/Au:N/C:N/I:N/A:P
Access Vector Network
Access Complexity Low
Authentication None
Confidentiality Impact None
Integrity Impact None
Availability Impact Partial
CVSS v3 Scores
CVSS detail National Vulnerability Database
Base Score 7.5
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact None
Integrity Impact None
Availability Impact High
CVSSv3 Version 3.1
SUSE Bugzilla entry: 1184428 [IN_PROGRESS]

SUSE Security Advisories:

List of released packages

Product(s) Fixed package version(s) References
SUSE Package Hub 15 SP2
  • syncthing >= 1.15.1-bp152.2.3.1
  • syncthing-relaysrv >= 1.15.1-bp152.2.3.1
 Patchnames:
openSUSE-2021-713
openSUSE Leap 15.2
  • syncthing >= 1.15.1-lp152.2.3.1
  • syncthing-relaysrv >= 1.15.1-lp152.2.3.1
 Patchnames:
openSUSE-2021-688
openSUSE Tumbleweed
  • syncthing >= 1.18.2-2.1
  • syncthing-relaysrv >= 1.18.2-2.1
 Patchnames:
openSUSE-Tumbleweed-2024-11417

Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.

Product(s) Source package State
Products past their end of life and not receiving proactive updates anymore.
SUSE Package Hub 15 SP2 syncthing Released

SUSE Timeline for this CVE

CVE page created: Wed Apr 7 04:24:35 2021
CVE page last modified: Thu Dec 11 16:53:25 2025