CVE-2026-58253

A flaw was found in NATS Server. When the noauthuser configuration is enabled, a parser optimization intended for client connections can inadvertently apply to route or leafnode listeners. This allows an unauthenticated attacker on an adjacent network to bypass inter-server authentication...

CVE-2026-58250

A flaw was found in NATS Server, a high-performance messaging system. An unauthenticated attacker with network access to a leafnode listener, where compression is enabled, could exploit this vulnerability. By sending repeated leafnode INFO protocol messages during the pre-authentication handshake...

NATS Server: Route API Auth Bypass

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NATS Server: MQTT retained and QoS replay bypass subscribe deny filters

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NATS Server: Subscribe Authz Bypass via Wildcard-Overlap

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NATS Server: Pre-auth server crash via double INFO in leafnode handshake

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CVE-2026-58207

A flaw was found in NATS Server. A client with the ability to send account-scoped connection monitoring requests could crash the server. This is achieved by providing pagination offset and limit values that cause an arithmetic overflow, leading to a Denial of Service DoS. Mitigation Upstream...

Improper Authorization

Overview github.com/nats-io/nats-server/server is an A simple, secure and performant communications system for digital systems, services and devices. Affected versions of this package are vulnerable to Improper Authorization via the queue subscription process. An attacker can gain unauthorized...

NULL Pointer Dereference

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 NULL Pointer Dereference via the leafnode handshake process. An attacker can cause the serve...

Incorrect Authorization

Overview github.com/nats-io/nats-server/server is an A simple, secure and performant communications system for digital systems, services and devices. Affected versions of this package are vulnerable to Incorrect Authorization due to insufficient enforcement of destination permission checks for...

Improper Authorization

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 Improper Authorization via the subscription authorization process. An attacker can access...

Incorrect Authorization

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 Incorrect Authorization due to insufficient enforcement of destination permission checks for...

Improper Authentication

Overview github.com/nats-io/nats-server/server is an A simple, secure and performant communications system for digital systems, services and devices. Affected versions of this package are vulnerable to Improper Authentication in the parser fast path for inter-server connections, which applies a...

Improper Authentication

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 Improper Authentication in the parser fast path for inter-server connections, which applies ...

Injection

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 Injection in the MQTT SUBSCRIBE handling, which forwards protocol control characters from...

Integer Overflow or Wraparound

Overview github.com/nats-io/nats-server/server is an A simple, secure and performant communications system for digital systems, services and devices. Affected versions of this package are vulnerable to Integer Overflow or Wraparound in the Connz connection monitoring pagination handler, which...

Integer Overflow or Wraparound

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 Integer Overflow or Wraparound in the Connz connection monitoring pagination handler, which...

Uncaught Exception

Overview github.com/nats-io/nats-server/server is an A simple, secure and performant communications system for digital systems, services and devices. Affected versions of this package are vulnerable to Uncaught Exception in the WebSocket listener routing, which dispatches requests for the...

CVE-2026-58211

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.12, a client could be registered as the configured noauthuser through a parser path used when the first client operation was not CONNECT, bypassing user-level connection...

CVE-2026-58208

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.12, a WebSocket listener could route requests for the MQTT-over-WebSocket path into MQTT handling even when MQTT was not configured, allowing an unauthenticated client with...