Configuration in nats-server - CVE-2021-32026
Published: May 4, 2021 / Updated: June 30, 2026
Vulnerability identifier: #VU135922
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2021-32026
CWE-ID: CWE-16
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: NATS - The Cloud Native Messaging System
Affected software:
nats-server
nats-server
Detailed vulnerability description
The vulnerability allows a remote attacker to negotiate unexpected TLS ciphersuites.
The vulnerability exists due to improper configuration handling in the TLS configuration logic when processing command-line TLS parameters. A remote attacker can initiate a TLS connection to negotiate unexpected TLS ciphersuites.
The issue occurs only when the server is started with TLS key and certificate settings supplied through command-line options.
How to mitigate CVE-2021-32026
Install security update from vendor's website.