CVE-2021-21404 is a denial-of-service vulnerability affecting Syncthing versions prior to 1.15.0. An attacker can crash the Syncthing relay server (strelaysrv) or the Syncthing client itself by sending a specially crafted relay message containing a negative length field. This vulnerability has a CVSS score of 7.5 (HIGH), indicating a network-based attack with low complexity and high impact on availability, but no impact on confidentiality or integrity. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage regarding this CVE.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
< 1.15.0CPE matchmatch criteria | cpe:2.3:a:syncthing:syncthing:*:*:*:*:*:*:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.
No media coverage found for this CVE.
The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.