PT-2026-56537

Name of the Vulnerable Software and Affected Versions NATS Server versions prior to 2.14.0 NATS Server versions prior to 2.12.7 NATS Server versions prior to 2.11.16 Description An authenticated user with subscription deny permissions can bypass a plain subject deny rule by utilizing a queue...

PT-2026-56583

Name of the Vulnerable Software and Affected Versions NATS Server versions prior to 2.14.3 NATS Server versions prior to 2.12.12 Description A flaw exists where a client can be registered as the configured no auth user via a parser path triggered when the initial client operation is not CONNECT...

PT-2026-56563

Name of the Vulnerable Software and Affected Versions NATS Server versions prior to 2.12.8 NATS Server versions prior to 2.11.17 Description An unauthenticated peer with network access to a leafnode listener with compression enabled can cause the server to crash. This occurs during the...

PT-2026-56581

Name of the Vulnerable Software and Affected Versions NATS Server versions prior to 2.14.3 NATS Server versions prior to 2.12.12 Description A client capable of sending account-scoped connection monitoring requests can cause the server to crash. This occurs when the client provides Offset and Lim...

CVE-2026-58251: Improper Authorization

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...

CVE-2026-58214: Incorrect Authorization

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, an authenticated MQTT client could subscribe to the internal $MQTT.deliver.pubrel subject family, bypassing configured subscribe permissions and exposing MQTT QoS2 protoc...

CVE-2026-58250: NULL Pointer Dereference

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...

CVE-2026-58254: Incorrect Authorization

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.8, message trace destination checks were applied to ordinary client connections but not consistently to messages arriving through leafnode connections, allowing a leafnode...

CVE-2026-58253: Improper Authentication

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, when noauthuser was configured, a parser fast path intended for ordinary client connections could also apply to route or leafnode listeners, allowing an...

CVE-2026-58210: Uncontrolled Resource Consumption

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, an unauthenticated MQTT client could cause the server to retain large incomplete MQTT CONNECT packets before authentication completed, consuming server memory while the...

CVE-2026-58213: Improper Neutralization of Special Elements in Output Used by a Downstream Component

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...

CVE-2026-58208: Uncaught Exception

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...

CVE-2026-58207: Integer Overflow or Wraparound

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 able to send account-scoped connection monitoring requests could crash the server by supplying Connz pagination Offset and Limit values that overflowed internal...

CVE-2026-58211: Incorrect Authorization

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...

PT-2026-56560

Name of the Vulnerable Software and Affected Versions NATS Server versions prior to 2.14.3 NATS Server versions prior to 2.12.12 Description An unauthenticated MQTT client can cause the server to consume excessive memory by sending large incomplete MQTT CONNECT packets. The server retains these...

PT-2026-56559

Name of the Vulnerable Software and Affected Versions NATS Server versions prior to 2.14.3 NATS Server versions prior to 2.12.12 Description MQTT retained message delivery and QoS1+ durable replay may deliver messages to subscribers even if the original topics match a configured subscribe deny...

PT-2026-56561

Name of the Vulnerable Software and Affected Versions NATS Server versions prior to 2.14.1 NATS Server versions prior to 2.12.9 Description An MQTT client can include protocol control characters in subscription filters. These characters are subsequently forwarded as NATS protocol data to route or...

nats-server: NATS Server: Information disclosure via MQTT client subscription bypass

A flaw was found in NATS Server, a high-performance messaging system. An authenticated MQTT Message Queuing Telemetry Transport client could bypass security permissions by subscribing to an internal subject family. This unauthorized access allows the client to view sensitive MQTT Quality of Servi...

nats-server: NATS Server: Denial of Service via incomplete MQTT CONNECT packets

A flaw was found in NATS Server. An unauthenticated remote attacker could send large, incomplete MQTT CONNECT packets to the server. This action causes the server to retain these packets, consuming significant memory before authentication is complete. This can lead to a denial of service DoS...

nats-server: NATS Server: Denial of Service via inconsistent message trace destination checks

A flaw was found in NATS Server. Message trace destination checks, which ensure that trace events are sent to authorized subjects, were not consistently applied to messages originating from leafnode connections. This inconsistency allows a leafnode operator to bypass these checks and send trace...