CVE-2020-26521

CVE-2020-26521 affects NATS server’s JWT handling: the JWT library (used by nats-server) can dereference nil during decoding, causing Denial of Service. Affected: NATS Server versions before 2.1.9. Root cause: nil dereference in Go code when processing User JWTs. Remediation: upgrade the JWT depe...

CVE-2020-26892

Summary : CVE-2020-26892 affects NATS nats-server before 2.1.9 due to incorrect access control from how expired credentials are handled in the JWT library. The vulnerability stems from the JWT package’s credential expiry checks, which could allow bypassing access restrictions. Affected versions i...

CVE-2019-13126

CVE-2019-13126 is an integer overflow in the NATS Server prior to 2.0.2 that allows a remote attacker to crash the server by sending a crafted request; if authentication is enabled, the attacker must have authenticated first. Public notices extend risk to later versions (e.g., GHSA references for...

CVE-2026-27571

NATS-Server WebSockets handling is vulnerable to a pre-auth memory DoS via a compression bomb. Prior to v2.11.2 and v2.12.3, memory bounds for a NATS message were not independently applied to the memory stream, allowing excessive memory consumption and potential OS termination. The issue is explo...

CVE-2026-33247

CVE-2026-33247 affects the NATS-Server (NATS.io). Prior to versions 2.11.15 and 2.12.6, running nats-server with static credentials provided via argv causes those credentials to be visible to any user who can see the monitoring port; the /debug/vars endpoint exposes an unredacted argv. A fix is a...

CVE-2026-58253

NATS Server (affected: prior to 2.14.0, 2.12.7, and 2.11.16) contains a parser fast path vulnerability where no_auth_user handling could apply to route/leafnode listeners, enabling an unauthenticated peer to bypass inter‑server CONNECT authentication and operate with the privileges of that connec...

CVE-2026-33217

CVE-2026-33217 affects NATS-Server prior to versions 2.11.15 and 2.12.6, where ACLs on message subjects were not applied in the $MQTT.> namespace, letting MQTT clients bypass ACL checks for MQTT subjects. Root cause: ACLs not enforced in that namespace. Impact: potential unauthorized access/by...

CVE-2026-33218

CVE-2026-33218 affects NATS-Server. Prior to versions 2.11.15 and 2.12.6, a client able to reach the leafnode port can crash the server with a specially malformed message before authentication. Versions 2.11.15 and 2.12.6 include a fix. Affected product: NATS-Server (leafnode handling). Root caus...

CVE-2026-33222

NATS-Server (JetStream) contains an authorization bypass via the JetStream management API: users with JetStream admin API access to restore one stream could restore to other stream names, risking data overwrite across streams. Affected versions are prior to 2.11.15 and 2.12.6. The fixed releases ...

CVE-2026-33223

CVE-2026-33223 affects NATS-Server. Prior to versions 2.11.15 and 2.12.6, the Nats-Request-Info header, intended to guarantee identity, could still be stripped incompletely from inbound messages, allowing an attacker with valid credentials to spoof identity to services relying on that header. The...

CVE-2026-58214

CVE-2026-58214 – NATS Server (MQTT subscribe ACL bypass) Prior to version 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 protocol metadata for sessions in the a...

CVE-2026-29785

CVE-2026-29785 affects the NATS-Server (NATS.io) prior to versions 2.11.14 and 2.12.5. When leafnode is enabled (not default) and compression is enabled (default with leafnodes), an unauthenticated attacker who can connect can crash the server by triggering a panic. The condition is pre-authentic...

CVE-2026-33216

Impactful CVE-2026-33216 (NATS-Server) : In MQTT deployments using usercodes/passwords, passwords are incorrectly classified as a non-authenticating identity statement (JWT) and exposed through monitoring endpoints. Affected versions are prior to 2.11.15 and 2.12.6; fixes are in 2.11.14 and 2.12....

CVE-2026-33219

CVE-2026-33219 affects NATS-Server (NATS.io) before versions 2.11.15 and 2.12.6. A malicious client connecting to the WebSockets port can trigger unbounded memory growth in nats-server prior to authentication by sending a large amount of data. This is a milder variant of CVE-2026-27571 and requir...

CVE-2026-33248

NATS-Server has an authentication bypass vulnerability in mTLS verify_and_map where certain RDN patterns in the client certificate Subject DN were not correctly enforced. A valid certificate from a trusted CA could bypass identity checks on versions prior to 2.11.15 and 2.12.6. The issue is consi...

CVE-2026-58209

NATS Server before versions 2.14.3 and 2.12.12 could deliver MQTT retained messages and QoS1+ durable replays to subscribers whose topics matched a deny rule, because delivery paths did not consistently re-check the original topic before sending MQTT PUBLISH. This issue is fixed in 2.14.3 and 2.1...

CVE-2026-58213

NATS Server (nats-server) before versions 2.14.1 and 2.12.9 is vulnerable: an MQTT client can include protocol control characters in subscription filters, which are later forwarded as NATS protocol data to route or leafnode connections. This corrupts the forwarded protocol stream and allows injec...

CVE-2026-33246

CVE-2026-33246 affects the NATS-Server (NATS.io). The issue is that the Nats-Request-Info: header used for identity could be spoofed when a leafnode connects to a nats-server, potentially enabling identity claims to be misrepresented. The root cause is header spoofing in leafnode connections; the...

CVE-2026-58250

CVE-2026-58250 affects NATS Server: an unauthenticated peer with access to a leafnode listener with compression enabled could crash the server during the pre-authentication leafnode handshake by sending repeated leafnode INFO messages. The issue is fixed in versions 2.12.8 and 2.11.17 . Exploitat...

CVE-2026-58251

CVE-2026-58251 affects NATS Server prior to version 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 evaluation could override the plain subject deny result when ...

CVE-2026-58252

CVE-2026-58252 affects NATS Server prior to versions 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 of it; queue subscriptions could also affect delivery...

CVE-2026-58254

NATS Server (affected components: leafnode message trace destination checks) could allow a leafnode operator to send trace events to subjects that should be disallowed and use trace-only behavior to interfere with delivery/storage. Root cause: checks were applied to ordinary client connections bu...

CVE-2026-58210

CVE-2026-58210 affects NATS Server prior to versions 2.14.3 and 2.12.12. An unauthenticated MQTT client could cause the server to retain large incomplete MQTT CONNECT packets before authentication completes, exhausting memory due to the parser waiting for the advertised MQTT packet length. The is...