CVE-2023-46129

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 cryptographic key handling library, nkeys, recently gained support for encryption, not just for signing/authentication. This is used in nats-server 2.10 (Sep 2023) and newer for authentication callouts.

Problem Description

The nkeys library's "xkeys" encryption handling logic mistakenly passed an array by value into an internal function, where the function mutated that buffer to populate the encryption key to use. As a result, all encryption was actually to an all-zeros key.

This affects encryption only, not signing.
FIXME: FILL IN IMPACT ON NATS-SERVER AUTH CALLOUT SECURITY.

Affected versions

nkeys Go library:

• 0.4.0 up to and including 0.4.5
• Fixed with nats-io/nkeys: 0.4.6

NATS Server:

• 2.10.0 up to and including 2.10.3
• Fixed with nats-io/nats-server: 2.10.4

Credits

Problem reported by Quentin Matillat (GitHub @tinou98).

CVE-2023-46129 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.4.6, 2.10.4); upgrading removes the vulnerable code path.

Kodem intelligence

Upgrade the nats-server.
For any application handling auth callouts in Go, if using the nkeys library, update the dependency, recompile and deploy that in lockstep.

1. What is CVE-2023-46129? CVE-2023-46129 is a high-severity security vulnerability in github.com/nats-io/nkeys (go), affecting versions >= 0.4.0, <= 0.4.5. It is fixed in 0.4.6, 2.10.4.
2. How severe is CVE-2023-46129? CVE-2023-46129 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2023-46129?
   • github.com/nats-io/nkeys (go) (versions >= 0.4.0, <= 0.4.5)
   • github.com/nats-io/nats-server/v2 (go) (versions >= 2.10.0, <= 2.10.3)
4. Is there a fix for CVE-2023-46129? Yes. CVE-2023-46129 is fixed in 0.4.6, 2.10.4. Upgrade to this version or later.
5. Is CVE-2023-46129 exploitable, and should I be worried? Whether CVE-2023-46129 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2023-46129 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2023-46129?
   • Upgrade github.com/nats-io/nkeys to 0.4.6 or later
   • Upgrade github.com/nats-io/nats-server/v2 to 2.10.4 or later