CVE-2026-85184
Auth bypass in @fastify/middie via absolute-form request targets
Is CVE-2026-85184 being exploited?
Not confirmed. CVE-2026-85184 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.33% probability of exploitation in the next 30 days.
How severe is CVE-2026-85184?
CVE-2026-85184 is rated Critical with a CVSS score of 9.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-85184?
Yes. A fix has been recorded for CVE-2026-85184. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-85184 affect?
CVE-2026-85184 affects @fastify/middie >=9.1.0 <9.3.4, Fastify applications using path-scoped middie middleware. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-85184?
Upgrade @fastify/middie to >=9.3.4 and validate/request-target handling
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated attackers can bypass path-scoped middleware (auth/authz) and reach route handlers using absolute-form request targets.
Immediate action required
- affected>= 9.1.0 and < 9.3.4
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.