critical severityConfidence highHistorical record

Fastify middie absolute-form requests can skip auth

@fastify/middie before 9.3.4 allows absolute-form requests to skip path-scoped middleware auth. Upgrade to 9.3.4.

Also tracked as CVE-2026-85184 · @fastify/middie absolute-form bypass

First observed

Sep 4, 2026

Last observed

Sep 4, 2026

Last reviewed

Sep 20, 2026

Tracking ended

Sep 4, 2026

JSON recordArtifact CSVSTIX 2.1 bundle

Uncertainty and limitations

Read the evidence limits before acting on this record.

Confirm whether your app uses path-scoped middie middleware.

  • Scoped to absolute-form request + path-scoped middie middleware.
  • Fixed version 9.3.4 from GHSA.
  • HOL blog is operator guidance.

Timeline

Reviewed events, oldest first, each tied to a verified source.

  1. Disclosure

    CVE-2026-85184 @fastify/middie absolute-form middleware bypass disclosed.

  2. Update

    HOL Guard published operator coverage for CVE-2026-85184.

Publication clock: 403.6 hours from reviewed disclosure timestamp to HOL publication; 12-hour critical target; historical backfill outside target.

Guard coverage and non-coverage

What Guard's reviewed coverage assertions do and do not claim for this campaign.

No Guard coverage mapping is published for this record.

Defensive policy guidance

Reviewed starting points for defending against this campaign's artifact classes.

No campaign-specific policy guidance is published.

Reviewed artifacts and indicators

Published values are defanged (for example hxxps and [.] blocks) so nothing here is copy-paste executable.

Reviewed artifacts

The specific artifacts this record concerns, as reviewed. Names and versions are shown as text; a registry link is not recorded here.

  • @fastify/middie@>=9.1.0 <9.3.4npmpackage

Sources

Every claim on this record is traceable to the sources below.

Reviewed in full by HOL Guard Security Publishing.

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Record HGTC-2026-21EC3D3F.