CVE•Published 2026-02-27•Modified 2026-05-14•1 article on news•6 live references•NVD data

CVE-2026-2880Fastify · Fastify\/middie

Vulnerability data via NVD (ingested)

CVSS v3.1

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS percentile

Exploit Prediction Scoring System · top 77% of all CVEs

Weaknesses (CWE)

CWE-20Improper Input Validation

Description

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.

Timeline

Published 2026-02-27

Modified 2026-05-14

External references

NVD MITRE Exploit-DB GitHub PoC Sploitus VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-2880

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Fastify Fastify\/middie"

All exposed Fastify Fastify\/middie instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Fastify\/middie"

HTTP body or banner mentions "Fastify\/middie" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-2880