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TI-2026-02474 Aliases CVE-2026-2880GHSA-8p85-9qpw-fwgw

@fastify/middie has an improper path normalization vulnerability

Priority LOW 36CWE-20Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.

Summary

A vulnerability in @fastify/middie versions < 9.2.0 can result in authentication/authorization bypass when using path-scoped middleware (for example, app.use('/secret', auth)). When Fastify router normalization options are enabled (such as ignoreDuplicateSlashes, useSemicolonDelimiter, and related trailing-slash behavior), crafted request paths may bypass middleware checks while still being routed to protected handlers.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0043 37th percentileScored 2026-11-07
Fix Fixed @fastify/middie (@fastify/middie): 9.2.0@fastify/middie (npm): 9.2.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
fastify@fastify/middie0.0.0 to before 9.2.09.2.0Patch availableCNA
—@fastify/middie (npm)before 9.2.09.2.0Patch availableGHSA-8p85-9qpw-fwgw
  • @fastify/middie Vendorfastify Affected 0.0.0 to before 9.2.0 Fixed in 9.2.0 Patch available CNA
  • @fastify/middie (npm) Vendor— Affected before 9.2.0 Fixed in 9.2.0 Patch available GHSA-8p85-9qpw-fwgw

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:fastify:fastify\/middie:*:*:*:*:*:node.js:*:*before 9.2.0Vulnerablefastify
  • cpe:2.3:a:fastify:fastify\/middie:*:*:*:*:*:node.js:*:* Versions before 9.2.0 Vulnerable ·fastify

Remediation

  • Fix · CNA @fastify/middie (@fastify/middie) Fixed in 9.2.0
  • Fix · GHSA-8p85-9qpw-fwgw @fastify/middie (npm) Fixed in 9.2.0 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-2880
  2. 2026-10-03 Alias added: GHSA-8p85-9qpw-fwgw

References

Advisory 2

Other 5

  • TI-2026-05498 @fastify/middie vulnerable to middleware authentication bypass in child plugin scopes CVSS 3.1CRITICAL 9.1
  • TI-2026-17725 Fastify Middie Middleware Path Bypass CVSS 3.1HIGH 8.8
  • TI-2026-58517 @fastify/middie vulnerable to path-scoped middleware bypass via absolute-form request target CVSS 3.1CRITICAL 9.1
  • TI-2026-12029 @fastify/middie vulnerable to authorization bypass via encoded slash in path parameter values CVSS 3.1CRITICAL 9.1
  • TI-2026-26176 @fastify/middie vulnerable to middleware bypass via deprecated ignoreDuplicateSlashes option CVSS 3.1CRITICAL 9.1
  • TI-2026-12013 @fastify/middie standalone engine vulnerable to Denial of Service via malformed percent-encoded paths CVSS 3.1HIGH 7.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences