CVE-2022-24450

(This advisory is canonically https://advisories.nats.io/CVE/CVE-2022-24450.txt)

Problem Description

NATS nats-server through 2022-02-04 has Incorrect Access Control, with unchecked ability for clients to authorize into any account, because of a coding error in a long-extant experimental feature.

A client crafting the initial protocol-level handshake could, with valid credentials for any account, specify a target account and switch into it immediately. This includes any other tenant, and includes the System account which controls nats-server core operations.

For deployments not using multi-tenancy through NATS Accounts, there is still a vulnerability: normal users are able to choose to be in the System account.

An experimental feature to provide dynamically provisioned sandbox accounts was designed to allow a server administrator to turn on an option to allow clients to dynamically request a brand new account inline at connection time. This feature went nowhere, but lived on in the code and was used by a number of tests; support was never added to any client libraries or to the documentation.

A bug in handling the feature meant that if someone did in fact have valid account credentials, then they could specify any other existing account and they would be assigned into that account.

Release 2.7.2 of nats-server removes the feature.
Because of the lack of client support and absence from protocol documentation, we feel this is safe operationally as well as the safest fix for the code.

Affected versions

NATS Server

• All 2.x versions up to and including 2.7.1.
• Fixed with nats-io/nats-server: 2.7.2
• NATS Server 1.x did not have accounts.
• Docker image: nats https://hub.docker.com/_/nats

NATS Streaming Server

• All versions embedding affected NATS Server:
  • Affected: v0.15.0 up to and including v0.24.0
  • Fixed with nats-io/nats-streaming-server: 0.24.1
• Docker image: nats-streaming https://hub.docker.com/_/nats-streaming

Workaround

None.

Existing users could act in any account, including the System account.

The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.

CVE-2022-24450 has a CVSS score of 8.8 (High). The vector is network-reachable, low 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 (0.24.1, 2.7.2); upgrading removes the vulnerable code path.

Kodem intelligence

Upgrade the NATS server.

1. What is CVE-2022-24450? CVE-2022-24450 is a high-severity incorrect authorization vulnerability in github.com/nats-io/nats-streaming-server (go), affecting versions >= 0.15.0, < 0.24.1. It is fixed in 0.24.1, 2.7.2. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
2. How severe is CVE-2022-24450? CVE-2022-24450 has a CVSS score of 8.8 (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-2022-24450?
   • github.com/nats-io/nats-streaming-server (go) (versions >= 0.15.0, < 0.24.1)
   • github.com/nats-io/nats-server/v2 (go) (versions >= 2.0.0, < 2.7.2)
4. Is there a fix for CVE-2022-24450? Yes. CVE-2022-24450 is fixed in 0.24.1, 2.7.2. Upgrade to this version or later.
5. Is CVE-2022-24450 exploitable, and should I be worried? Whether CVE-2022-24450 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-2022-24450 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-2022-24450?
   • Upgrade github.com/nats-io/nats-streaming-server to 0.24.1 or later
   • Upgrade github.com/nats-io/nats-server/v2 to 2.7.2 or later