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Security Advisories

CVE-2026-27889

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-27889

Severity

7.5

High

CVSS V3

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Summary

NATS: Pre-auth remote server crash via WebSocket frame length overflow in wsRead

Description

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.2.0 and prior to versions 2.11.14 and 2.12.5, a missing sanity check on a WebSockets frame could trigger a server panic in the nats-server. This happens before authentication, and so is exposed to anyone who can connect to the websockets port. Versions 2.11.14 and 2.12.5 contains a fix. A workaround is available. The vulnerability only affects deployments which use WebSockets and which expose the network port to untrusted end-points. If one is able to do so, a defense in depth of restricting either of these will mitigate the attack.

References

Affected packages


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