Is CVE-2026-27889 actively exploited?

No active exploitation of CVE-2026-27889 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-27889 be exploited remotely?

Yes. CVE-2026-27889 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-27889?

CVE-2026-27889 has a CVSS score of 7.5 (HIGH).

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HIGH

CVE-2026-27889

CWE-190Published: March 25, 2026· Updated: Mar 26, 2026

7.5

CVSS v3.1

EPSS:0.07%probability of exploitation in 30 daysPercentile:21.3th

Official 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.

NVD Source

Technical Analysis

CVE-2026-27889 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.