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

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-14181— @fastify/middie standalone engine vulnerable to Denial of Service via malformed percent-encoded paths

Quick assessment

Affected
@fastify/middie @fastify/middie
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.

Fastify @fastify/middie是Fastify团队开源的一个中间件引擎。 Fastify @fastify/middie 9.1.0至9.3.2版本存在异常处理不当漏洞，该漏洞源于URL规范化步骤未正确处理包含畸形百分号编码序列的请求路径，可能导致Node.js进程终止并造成拒绝服务。

CVSS 7.5 · High EPSS 0.50% · P41

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 2

VendorProduct Version RangeStatus
@fastify/middie @fastify/middie 9.1.0< 9.3.3 affected
9.3.3 unaffected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-14181

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Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.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
@fastify/middie standalone engine vulnerable to Denial of Service via malformed percent-encoded paths
Source: CVE Program / CVE List V5
Vulnerability Description
@fastify/middie versions 9.1.0 through 9.3.2 fail to guard the URL normalization step used by the standalone engine when incoming request paths contain malformed percent-encoded sequences. Inputs such as an incomplete percent escape or a truncated multibyte sequence cause the underlying decoder to throw synchronously, and the exception escapes the middie normalize step and terminates the Node.js process. The bypass affects applications that call middie.run directly on the standalone engine API, causing an immediate denial of service for all connected clients until restart. Applications using the Fastify plugin path are not affected because Fastifys error handler catches the exception. Patches: upgrade to @fastify/middie 9.3.3. Workarounds: migrate from the standalone engine API to the Fastify plugin path, where the framework error handler catches the exception.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
未捕获的异常
Source: CVE Program / CVE List V5
Vulnerability Title
Fastify @fastify/middie 异常处理不当漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Fastify @fastify/middie是Fastify团队开源的一个中间件引擎。 Fastify @fastify/middie 9.1.0至9.3.2版本存在异常处理不当漏洞，该漏洞源于URL规范化步骤未正确处理包含畸形百分号编码序列的请求路径，可能导致Node.js进程终止并造成拒绝服务。
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
@fastify/middie @fastify/middie 9.1.0 ~ 9.3.3 -

II. Public POCs for CVE-2026-14181

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 6148 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-2026-14181

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-14181 (1)

IV. Related Vulnerabilities

Same product: @fastify/middie
Same vendor: @fastify/middie
Same weakness: CWE-248

V. Comments for CVE-2026-14181

No comments yet

Leave a comment