BIT-NATS-2026-58213 NATS Server: MQTT SUBSCRIBE Protocol Injection via Leaf Node/Route Forwarding allows arbitrary NATS command injection

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.1 and 2.12.9, an MQTT client could include protocol control characters in subscription filters that were later forwarded as NATS protocol data to route or leafnode connections, corrupti...

BIT-NATS-2026-58209 NATS Server: MQTT retained and QoS replay bypass subscribe deny filters

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, MQTT retained message delivery and QoS1+ durable replay could deliver messages whose original topics matched a subscriber configured subscribe deny rule because these...

PT-2026-58920

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.0, 2.12.7, and 2.11.16, an authenticated user with subscription deny permissions could bypass a plain subject deny rule by using a queue subscription, because queue-specific deny...

PT-2026-58919

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.12.8 and 2.11.17, an unauthenticated peer with network access to a leafnode listener with compression enabled could crash the server during the pre-authentication leafnode handshake by...

PT-2026-58917

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.1 and 2.12.9, an MQTT client could include protocol control characters in subscription filters that were later forwarded as NATS protocol data to route or leafnode connections, corrupti...

PT-2026-58921

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.0, 2.12.7, and 2.11.16, an authenticated user could receive messages on denied subjects when a wildcard subscription overlapped with a configured wildcard deny rule but was not a subset...

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

...

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

...

NATS Server: Subscribe Authz Bypass via Wildcard-Overlap

...

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

...

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...

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 in the MQTT retained message delivery and QoS1+ durable replay...

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 ...