CVE-2020-28466

This affects all versions of package github.com/nats-io/nats-server/server. Untrusted accounts are able to crash the server using configs that represent a service export/import cycles. Disclaimer from the maintainers - Running a NATS service which is exposed to untrusted users presents a heightened risk. Any remote execution flaw or equivalent seriousness, or denial-of-service by unauthenticated users, will lead to prompt releases by the NATS maintainers. Fixes for denial of service issues with no threat of remote execution, when limited to account holders, are likely to just be committed to the main development branch with no special attention. Those who are running such services are encouraged to build regularly from git.

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

CVE-2020-28466 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 (2.2.0); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2020-28466? CVE-2020-28466 is a high-severity uncontrolled resource consumption vulnerability in github.com/nats-io/nats-server (go), affecting versions < 2.2.0. It is fixed in 2.2.0. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
2. How severe is CVE-2020-28466? CVE-2020-28466 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-2020-28466?
   • github.com/nats-io/nats-server (go) (versions < 2.2.0)
   • github.com/nats-io/nats-server/v2 (go) (versions < 2.2.0)
4. Is there a fix for CVE-2020-28466? Yes. CVE-2020-28466 is fixed in 2.2.0. Upgrade to this version or later.
5. Is CVE-2020-28466 exploitable, and should I be worried? Whether CVE-2020-28466 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-2020-28466 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-2020-28466?
   • Upgrade github.com/nats-io/nats-server to 2.2.0 or later
   • Upgrade github.com/nats-io/nats-server/v2 to 2.2.0 or later