Linuxfoundation Nats-Server vulnerabilities

CVE-2026-33216 [HIGH] CWE-256 CVE-2026-33216: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prio NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, for MQTT deployments using usercodes/passwords: MQTT passwords are incorrectly classified as a non-authenticating identity statement (JWT) and exposed via monitoring endpoints. Versions 2.11.14 and 2.12.6 contain a fix.

CVE-2026-27889 [HIGH] CWE-190 CVE-2026-27889: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Star 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 websocke

CVE-2026-29785 [HIGH] CWE-476 CVE-2026-29785: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prio NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.14 and 2.12.5, if the nats-server has the "leafnode" configuration enabled (not default), then anyone who can connect can crash the nats-server by triggering a panic. This happens pre-authentication and requires that compression be en

CVE-2026-33218 [HIGH] CWE-20 CVE-2026-33218: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prio NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, a client which can connect to the leafnode port can crash the nats-server with a certain malformed message pre-authentication. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable leafnode support if not n

CVE-2026-33247 [MEDIUM] CWE-215 CVE-2026-33247: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prio NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, if a nats-server is run with static credentials for all clients provided via argv (the command-line), then those credentials are visible to any user who can see the monitoring port, if that too is enabled. The `/debug

CVE-2026-33249 [MEDIUM] CWE-863 CVE-2026-33249: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Star NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.11.0 and prior to versions 2.11.15 and 2.12.6, a valid client which uses message tracing headers can indicate that the trace messages can be sent to an arbitrary valid subject, including those to which the client does not have publis

CVE-2026-33246 [MEDIUM] CWE-287 CVE-2026-33246: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server offers a `Nats-Request-Info:` message header, providing information about a request. This is supposed to provide enough information to allow for account/user identification, such that NATS clients could make their own decisions on how to tr

CVE-2026-33223 [MEDIUM] CWE-290 CVE-2026-33223: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prio NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, the NATS message header `Nats-Request-Info:` is supposed to be a guarantee of identity by the NATS server, but the stripping of this header from inbound messages was not fully effective. An attacker with valid credent

CVE-2026-33222 [MEDIUM] CWE-285 CVE-2026-33222: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prio NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, users with JetStream admin API access to restore one stream could restore to other stream names, impacting data which should have been protected against them. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround

CVE-2026-33219 [MEDIUM] CVE-2026-33219: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prio NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, a malicious client which can connect to the WebSockets port can cause unbounded memory use in the nats-server before authentication; this requires sending a corresponding amount of data. This is a milder variant of CVE-2026-2

CVE-2026-33248 [MEDIUM] CWE-287 CVE-2026-33248: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prio NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, when using mTLS for client identity, with `verify_and_map` to derive a NATS identity from the client certificate's Subject DN, certain patterns of RDN would not be correctly enforced, allowing for authentication bypas

CVE-2026-33217 [MEDIUM] CWE-863 CVE-2026-33217: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prio NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, when using ACLs on message subjects, these ACLs were not applied in the `$MQTT.>` namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects. Versions 2.11.15 and 2.12.6 contain a fix. No known workaround

CVE-2026-33215 [MEDIUM] CWE-287 CVE-2026-33215: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server provides an MQTT client interface. Prior to versions 2.11.15 and 2.12.5, Sessions and Messages can by hijacked via MQTT Client ID malfeasance. Versions 2.11.15 and 2.12.5 patch the issue. No known workarounds are available.

CVE-2026-27571 [HIGH] CWE-409 CVE-2026-27571: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The WebSockets handling of NATS messages handles compressed messages via the WebSockets negotiated compression. Prior to versions 2.11.2 and 2.12.3, the implementation bound the memory size of a NATS message but did not independently bound the memory consump

CVE-2025-30215 [CRITICAL] CVE-2025-30215: NATS-Server is a High-Performance server for NATS NATS-Server is a High-Performance server for NATS.io, the cloud and edge native messaging system. In versions starting from 2.2.0 but prior to 2.10.27 and 2.11.1, the management of JetStream assets happens with messages in the $JS. subject namespace in the system account; this is partially exposed into regular accounts to allow account holders to manage their assets. Some of the JS API requests were missi

CVE-2022-29946 [MEDIUM] CVE-2022-29946: NATS NATS.io NATS Server before 2.8.2 and Streaming Server before 0.24.6 could allow a remote attacker to bypass security restrictions, caused by the failure to enforce negative user permissions in one scenario. By using a queue subscription on the wildcard, an attacker could exploit this vulnerability to allow denied subjects.

CVE-2023-46129 [HIGH] CWE-321 CVE-2023-46129: NATS.io is a high performance open source pub-sub distributed communication technology, built for th NATS.io is a high performance open source pub-sub distributed communication technology, built for the cloud, on-premise, IoT, and edge computing. The cryptographic key handling library, nkeys, recently gained support for encryption, not just for signing/authentication. This is used in nats-server 2.10 (Sep 2023) and newer for authentication callouts.

CVE-2023-47090 [MEDIUM] CWE-863 CVE-2023-47090: NATS nats-server before 2.9.23 and 2.10.x before 2.10.2 has an authentication bypass. An implicit $G NATS nats-server before 2.9.23 and 2.10.x before 2.10.2 has an authentication bypass. An implicit $G user in an authorization block can sometimes be used for unauthenticated access, even when the intention of the configuration was for each user to have an account. The earliest affected version is 2.2.0.

CVE-2022-28357 [CRITICAL] CWE-22 CVE-2022-28357: NATS nats-server 2.2.0 through 2.7.4 allows directory traversal because of an unintended path to a m NATS nats-server 2.2.0 through 2.7.4 allows directory traversal because of an unintended path to a management action from a management account.

CVE-2022-26652 [MEDIUM] CWE-22 CVE-2022-26652: NATS nats-server before 2.7.4 allows Directory Traversal (with write access) via an element in a ZIP NATS nats-server before 2.7.4 allows Directory Traversal (with write access) via an element in a ZIP archive for JetStream streams. nats-streaming-server before 0.24.3 is also affected.