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Vulnerability · Published Mar 25, 2026 · Assigned by GitHub_M

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

High 7.4

In plain English

A high-severity security flaw in nats-server from nats-io. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.4High
Exploit odds (30 days)0.4%top 62.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.23nats-server2.12.6-r0ALPINE-CVE-2026-33247
Alpine:v3.24nats-server2.12.6-r0ALPINE-CVE-2026-33247
Debian:12nats-serverno fix listedDEBIAN-CVE-2026-33247
Debian:13nats-serverno fix listedDEBIAN-CVE-2026-33247
Debian:14nats-server2.12.6-1DEBIAN-CVE-2026-33247
Gogithub.com/nats-io/nats-serverno fix listedGO-2026-4827
Gogithub.com/nats-io/nats-server/v22.11.15, 2.12.6GO-2026-4827
Gogithub.com/nats-io/nats-server/v22.11.15GHSA-x6g4-f6q3-fqvv
Gogithub.com/nats-io/nats-server/v22.12.6GHSA-x6g4-f6q3-fqvv
Ubuntu:24.04:LTSnats-serverno fix listedUBUNTU-CVE-2026-33247
Ubuntu:25.10nats-serverno fix listedUBUNTU-CVE-2026-33247
Ubuntu:26.10nats-serverno fix listedUBUNTU-CVE-2026-33247

Affected products (as reported)

VendorProductVersions
nats-io nats-server < 2.11.15>= 2.12.0-RC.1, < 2.12.6

Weakness: CWE-215, CWE-214 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References