Answer in brief
CVE-2026-14181 records a High severity (CVSS 7.5) vulnerability in @fastify/middie standalone engine vulnerable to Denial of Service via malformed percent-encoded paths. The current sources do not mark it as known exploited. The current feed maps @fastify/middie/@fastify/middie (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps @fastify/middie/@fastify/middie (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| @fastify/middie/@fastify/middiegeneric | >=9.1.0 <9.3.3 | 9.3.3 |
Published upstream
Jul 1, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 2, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 1, 2026
@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.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-14181 records a High severity (CVSS 7.5) vulnerability in @fastify/middie standalone engine vulnerable to Denial of Service via malformed percent-encoded paths. The current sources do not mark it as known exploited. The current feed maps @fastify/middie/@fastify/middie (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps @fastify/middie/@fastify/middie (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| @fastify/middie/@fastify/middiegeneric | >=9.1.0 <9.3.3 | 9.3.3 |
Published upstream
Jul 1, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 2, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 1, 2026
@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.
Quoted source text, attributed separately from HOL analysis.