Allocation of Resources Without Limits or Throttling Affecting github.com/nats-io/nats-server/v2/server package, versions <2.11.12>=2.12.0-RC.1 <2.12.3
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-GOLANG-GITHUBCOMNATSIONATSSERVERV2SERVER-15347992
- published25 Feb 2026
- disclosed24 Feb 2026
- creditPavel Kohout
Introduced: 24 Feb 2026
CVE-2026-27571 Â (opens in a new tab)How to fix?
Upgrade github.com/nats-io/nats-server/v2/server to version 2.11.12, 2.12.3 or higher.
Overview
github.com/nats-io/nats-server/v2/server is an A simple, secure and performant communications system for digital systems, services and devices.
Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the WebSockets handling of NATS compressed messages. An attacker can cause excessive memory consumption, potentially leading to the termination of the server process by sending specially crafted compressed messages before authentication.
Note: This is only exploitable if WebSockets are enabled and the network port is exposed to untrusted endpoints.