GHSA-x6g4-f6q3-fqvv BIT-nats-2026-33247 CVE-2026-33247 GO-2026-4827
NATS credentials are exposed in monitoring port via command-line argv
- Severity
- 7.4 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.43%
- Chance of exploitation in the next 30 days. Higher than 37.22% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-215 Insertion of Sensitive Information Into Debugging Code
- Fix
2.11.15- Upgrade github.com/nats-io/nats-server/v2 to this version or later
Description
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.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/nats-io/nats-server | all versions |
No fix yet |
| github.com/nats-io/nats-server/v2 | < 2.11.15 |
2.11.15 |
| github.com/nats-io/nats-server/v2 | >= 2.12.0-RC.1, < 2.12.6 |
2.12.6 |
| github.com/nats-io/nats-server/v2 | < 2.11.15>= 2.12.0-RC.1, < 2.12.6 |
2.11.152.12.6 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/nats-io/nats-server/v2 Go → 2.11.15
- go
go get github.com/nats-io/nats-server/v2@v2.11.15 && go mod tidy
Severity breakdown
CVSS 3.1 7.4
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Weakness
CWE-215: Insertion of Sensitive Information Into Debugging Code
The product inserts sensitive information into debugging code, which could expose this information if the debugging code is not disabled in production.
How to prevent it
- Implementation: Do not leave debug statements that could be executed in the source code. Ensure that all debug information is eradicated before releasing the software.
- Architecture and Design: Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
References
Advisories
Packages
Other links
- github.com/nats-io/nats-server/security/advisories/GHSA-x6g4-f6q3-fqvv
- advisories.nats.io/CVE/secnote-2026-14.txt
- pkg.go.dev/vuln/GO-2026-4827
- access.redhat.com/errata/RHSA-2026:21769
- access.redhat.com/errata/RHSA-2026:22347
- access.redhat.com/errata/RHSA-2026:23345
- access.redhat.com/security/cve/CVE-2026-33247
- bugzilla.redhat.com/show_bug.cgi
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33247.json
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-pq2q-rcw4-3hr6 NATS: Pre-auth remote server crash via WebSocket frame length overflow in wsRead | High | Also affects github.com/nats-io/nats-server |
| GHSA-3f24-pcvm-5jqc NATS has mTLS verify_and_map authentication bypass via incorrect Subject DN matching | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-55h8-8g96-x4hj NATS: Leafnode connections allow spoofing of Nats-Request-Info identity headers | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-pwx7-fx9r-hr4h NATS Server: Incomplete Stripping of Nats-Request-Info Header Allows Identity Spoofing | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-9983-vrx2-fg9c NATS JetStream has an authorization bypass through its Management API | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-8r68-gvr4-jh7j NATS is vulnerable to pre-auth DoS through WebSockets client service | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-vprv-35vv-q339 NATS has pre-auth server panic via leafnode handling | High | Also affects github.com/nats-io/nats-server |
| GHSA-jxxm-27vp-c3m5 NATS allows MQTT clients to bypass ACL checks | Medium | Also affects github.com/nats-io/nats-server |
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