CVE-2021-21404 – github.com/syncthing/syncthing

Package

Manager: go
Name: github.com/syncthing/syncthing
Vulnerable Version: >=0 <1.15.0

Severity

Level: Low

CVSS v3.1: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

EPSS: 0.00918 pctl0.75069

Details

Crash due to malformed relay protocol message ### Impact 1. `syncthing` can be caused to crash and exit if sent a malformed relay protocol message message with a negative length field. 2. The relay server `strelaysrv` can be caused to crash and exit if sent a malformed relay protocol message with a negative length field. At no point is sensitive data exposed or liable to be altered due to this issue. Sensitive data is never exposed to relay operators. Syncthing itself would need to be lured to connect to a malicious relay server in order to exploit the issue. ### Patches Fixed in version 1.15.0. ### Workarounds 1. No known workaround for `strelaysrv`. 2. `syncthing` can be configured to not use relays, or to only use specific, trusted relays. If Syncthing is used in a closed environment or with relaying disabled, i.e., it does not communicate with unknown relays, Syncthing is not vulnerable. ### For more information If you have any questions or comments about this advisory, please discuss it [on the forum](https://forum.syncthing.net/). Thanks to Wojciech Paciorek for discovering and reporting this issue.

Metadata

Created: 2021-05-21T16:23:17Z
Modified: 2021-05-20T20:52:26Z
Source: https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/05/GHSA-x462-89pf-6r5h/GHSA-x462-89pf-6r5h.json
CWE IDs: ["CWE-20"]
Alternative ID: GHSA-x462-89pf-6r5h
Finding: F184
Auto approve: 1