@fastify/middie vulnerable to path-scoped middleware bypass via absolute-form request target (CVE-2026-85184) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-85184

@fastify/middie vulnerable to path-scoped middleware bypass via absolute-form request target

Answer in brief

CVE-2026-85184 records a Unknown severity vulnerability in @fastify/middie vulnerable to path-scoped middleware bypass via absolute-form request target. 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.

Published Sep 4, 2026Updated Sep 4, 2026Source checked Sep 4, 2026First seen by HOL Sep 4, 2026Material review Sep 4, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. 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.

Affected scope and exposure questions

The current feed maps @fastify/middie/@fastify/middie (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
@fastify/middie/@fastify/middiegeneric	>=9.1.0 <9.3.4	9.3.4

Recommended response

Check inventory. Check lockfiles and deployed manifests for @fastify/middie/@fastify/middie.
Review the reported fix. Update @fastify/middie/@fastify/middie to 9.3.4 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 4, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 4, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 4, 2026

Sources and claim methodology

Upstream source description

@fastify/middie versions >= 9.1.0 and before 9.3.4 decide whether to run path-scoped middleware by matching against the raw request target, while the Fastify router resolves an absolute-form request target to its path before dispatching. Because the two layers evaluate different strings, a request using an absolute-form target reaches the route handler while the path-scoped middleware, such as authentication or authorization, is skipped. An unauthenticated network attacker can use this to bypass path-based access controls in a Fastify application that relies on middie for those controls. Users should upgrade to @fastify/middie 9.3.4 or later.

Quoted source text, attributed separately from HOL analysis.