{"id":"CVE-2026-2880","summary":"@fastify/middie has an improper path normalization vulnerability","details":"A vulnerability in @fastify/middie versions \u003c 9.2.0 can result in authentication/authorization bypass when using path-scoped middleware (for example, app.use('/secret', auth)).\n\nWhen 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.","aliases":["GHSA-8p85-9qpw-fwgw"],"modified":"2026-08-12T03:51:14.450411210Z","published":"2026-02-27T18:25:37.428Z","database_specific":{"cwe_ids":["CWE-20"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/2xxx/CVE-2026-2880.json","cna_assigner":"openjs"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/2xxx/CVE-2026-2880.json"},{"type":"ADVISORY","url":"https://github.com/fastify/middie/security/advisories/GHSA-8p85-9qpw-fwgw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-2880"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/fastify/middie","events":[{"introduced":"0"},{"fixed":"f9b3e79c2c045c9af8e5860d96629943ceeb61b0"}],"database_specific":{"cpe":"cpe:2.3:a:fastify:fastify\\/middie:*:*:*:*:*:node.js:*:*","extracted_events":[{"introduced":"0.0.0"},{"fixed":"9.2.0"},{"introduced":"0"}],"source":["AFFECTED_FIELD","CPE_RANGE"]}}],"versions":["v9.1.0","v9.0.3","v9.0.2","v9.0.1","v8.3.1","v9.0.0","v8.3.0","v8.2.0","v8.1.0","v8.0.0","v7.0.0","v6.0.0","v5.4.0","v5.3.0","v5.2.0","v5.1.0","v5.0.0","v4.1.0","v4.0.1","v3.2.1","v3.2.0","v4.0.0","v3.1.0","v3.0.0","v2.1.1","v2.1.0","v2.0.0","v1.1.0","v1.0.0","v0.3.0","v0.2.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-2880.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"}]}