Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-58214— NATS Server: MQTT subscribe ACL bypass via $MQTT.deliver.pubrel prefix (incomplete fix for CVE-2026-33217)

Quick assessment

Affected
nats-io nats-server
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Nats Server是Nats团队的一款服务端软件产品。 NATS Server存在授权问题漏洞，该漏洞源于授权问题，可能导致经过身份验证的MQTT客户端订阅内部$MQTT.deliver.pubrel subject系列，绕过配置的订阅权限并暴露账户中会话的MQTT QoS2协议元数据。以下版本受到影响：2.12.12之前版本和2.14.3之前版本。

CVSS 4.3 · Medium EPSS 0.35% · P27

Possible ATT&CK Techniques 1 AI

T1530 · Data from Cloud Storage

Affected Version Matrix 2

VendorProduct Version RangeStatus
nats-io nats-server < 2.12.12 affected
>= 2.14.0-RC.1, < 2.14.3 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-58214

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
NATS Server: MQTT subscribe ACL bypass via $MQTT.deliver.pubrel prefix (incomplete fix for CVE-2026-33217)
Source: CVE Program / CVE List V5
Vulnerability Description
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 $MQTT.deliver.pubrel subject family, bypassing configured subscribe permissions and exposing MQTT QoS2 protocol metadata for sessions in the account. This issue is fixed in versions 2.14.3 and 2.12.12.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
授权机制不正确
Source: CVE Program / CVE List V5
Vulnerability Title
NATS Server 授权问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Nats Server是Nats团队的一款服务端软件产品。 NATS Server存在授权问题漏洞，该漏洞源于授权问题，可能导致经过身份验证的MQTT客户端订阅内部$MQTT.deliver.pubrel subject系列，绕过配置的订阅权限并暴露账户中会话的MQTT QoS2协议元数据。以下版本受到影响：2.12.12之前版本和2.14.3之前版本。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
nats-io nats-server < 2.12.12 -

II. Public POCs for CVE-2026-58214

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-58214

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-58214 (2)

Vendor Advisories for CVE-2026-58214 (1)

Vendor Pages for CVE-2026-58214 (2)

Same Patch Batch · nats-io · 2026-07-08 · 12 CVEs total

CVE-2026-58253 8.8 HIGH NATS Server: Route API Auth Bypass
CVE-2026-58207 7.7 HIGH NATS Server: Remote crash via integer overflow in Connz pagination
CVE-2026-58250 7.5 HIGH NATS Server: Pre-auth server crash via double INFO in leafnode handshake
CVE-2026-58210 7.5 HIGH NATS Server: MQTT partial CONNECT packets can exhaust pre-auth memory
CVE-2026-58213 7.1 HIGH NATS Server: MQTT SUBSCRIBE Protocol Injection via Leaf Node/Route Forwarding allows arbit
CVE-2026-58208 6.8 MEDIUM NATS Server: MQTT-over-WebSocket Path Can Crash WebSocket-Only JetStream Servers Before MQ
CVE-2026-58251 6.5 MEDIUM NATS Server: Queue Subscribe Authz Bypass
CVE-2026-58252 6.5 MEDIUM NATS Server: Subscribe Authz Bypass via Wildcard-Overlap
CVE-2026-58211 5.4 MEDIUM NATS Server: `no_auth_user` pre-CONNECT fast path bypasses user connection restrictions
CVE-2026-58209 4.3 MEDIUM NATS Server: MQTT retained and QoS replay bypass subscribe deny filters
CVE-2026-58254 NATS Server: Incomplete fix for CVE-2026-33249: Leaf node connections bypass Nats-Trace-De

IV. Related Vulnerabilities

Same product: nats-server
Same vendor: nats-io
Same weakness: CWE-863

V. Comments for CVE-2026-58214

No comments yet

Leave a comment