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

Quick assessment

Affected
nats-io nats-server
Exploitation
Public or AI PoC available; prioritize validation
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 2.12.9之前版本和2.14.0-RC.1至2.14.1之前版本存在输入验证错误漏洞，该漏洞源于输入验证错误，可能导致MQTT客户端在订阅过滤器中包含协议控制字符，进而注入未预期的NATS协议操作。

CVSS 7.1 · High EPSS 0.44% · P37

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 2

VendorProduct Version RangeStatus
nats-io nats-server < 2.12.9 affected
>= 2.14.0-RC.1, < 2.14.1 affected
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I. Basic Information for CVE-2026-58213

Vulnerability Information
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Vulnerability Title
NATS Server: MQTT SUBSCRIBE Protocol Injection via Leaf Node/Route Forwarding allows arbitrary NATS command injection
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 2.14.1 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, corrupting the forwarded protocol stream and allowing injection of unintended NATS protocol operations. This issue is fixed in versions 2.14.1 and 2.12.9.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
输出中的特殊元素转义处理不恰当(注入)
Source: CVE Program / CVE List V5
Vulnerability Title
Nats Server 输入验证错误漏洞
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 2.12.9之前版本和2.14.0-RC.1至2.14.1之前版本存在输入验证错误漏洞，该漏洞源于输入验证错误，可能导致MQTT客户端在订阅过滤器中包含协议控制字符，进而注入未预期的NATS协议操作。
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 < 2.12.9 -

II. Public POCs for CVE-2026-58213

# POC Description Source Link Shenlong Link
AI-Generated POC Verified env Premium
Qwen3.6-35B-A3B · 11517 chars
Pro+ exclusive includes:
Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
In-depth vulnerability mechanism
Trigger conditions & impact
Full executable POC code
Exploit chain & mitigation
POC zip download
100+ AI POC generations per month

III. Intelligence Information for CVE-2026-58213

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Patches & Fixes for CVE-2026-58213 (5)

Vendor Advisories for CVE-2026-58213 (1)

Vendor Pages for CVE-2026-58213 (1)

Other References for CVE-2026-58213 (1)

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-2026-58208 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-2026-58214 4.3 MEDIUM NATS Server: MQTT subscribe ACL bypass via $MQTT.deliver.pubrel prefix (incomplete fix for
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-74

V. Comments for CVE-2026-58213

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