NATS credentials are exposed in monitoring port via command-line argv in github.com/nats-io/nats-server

Open Source Vulnerabilities BIT-nats-2026-33247

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, if a nats-server is run with static credentials for all clients provided via argv (the command-line), then those credentials are visible to any user who can see the monitoring port, if that too is enabled. The `/debug/vars` end-point contains an unredacted copy of argv. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, configure credentials inside a configuration file instead of via argv, and do not enable the monitoring port if using secrets in argv. Best practice remains to not expose the monitoring port to the Internet, or to untrusted network sources.

Open Source Vulnerabilities GO-2026-4827

NATS credentials are exposed in monitoring port via command-line argv in github.com/nats-io/nats-server

Open Source Vulnerabilities GHSA-x6g4-f6q3-fqvv

### Background NATS.io is a high performance open source pub-sub distributed communication technology, built for the cloud, on-premise, IoT, and edge computing. The nats-server provides an optional monitoring port, which provides access to sensitive data. The nats-server can take certain configuration options on the command-line instead of requiring a configuration file. ### Problem Description If a nats-server is run with static credentials for all clients provided via argv (the command-line), then those credentials are visible to any user who can see the monitoring port, if that too is enabled. The `/debug/vars` end-point contains an unredacted copy of argv. ### Patches Fixed in nats-server 2.12.6 & 2.11.15 ### Workarounds The NATS Maintainers are bemused at the concept of someone deploying a real configuration using `--pass` to avoid a config file, but also enabling monitoring. Configure credentials inside a configuration file instead of via argv. Do not enable the monitoring port if using secrets in argv. Best practice remains to not expose the monitoring port to the Internet, or to untrusted network sources.

Open Source Vulnerabilities CVE-2026-33247

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, if a nats-server is run with static credentials for all clients provided via argv (the command-line), then those credentials are visible to any user who can see the monitoring port, if that too is enabled. The `/debug/vars` end-point contains an unredacted copy of argv. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, configure credentials inside a configuration file instead of via argv, and do not enable the monitoring port if using secrets in argv. Best practice remains to not expose the monitoring port to the Internet, or to untrusted network sources.