@fastify/middie versions 9.3.1 and earlier are vulnerable to middleware bypass when the deprecated Fastify ignoreDuplicateSlashes option is enabled. The middleware path matching logic does not account for duplicate slash normalization performed by Fastify's router, allowing requests with duplicate slashes to bypass middleware authentication and authorization checks. This only affects applications using the deprecated ignoreDuplicateSlashes option. Upgrade to @fastify/middie 9.3.2 to fix this issue. There are no workarounds other than disabling the ignoreDuplicateSlashes option.
Metrics
Affected Vendors & Products
References
History
Thu, 16 Apr 2026 15:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Thu, 16 Apr 2026 14:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | @fastify/middie versions 9.3.1 and earlier are vulnerable to middleware bypass when the deprecated Fastify ignoreDuplicateSlashes option is enabled. The middleware path matching logic does not account for duplicate slash normalization performed by Fastify's router, allowing requests with duplicate slashes to bypass middleware authentication and authorization checks. This only affects applications using the deprecated ignoreDuplicateSlashes option. Upgrade to @fastify/middie 9.3.2 to fix this issue. There are no workarounds other than disabling the ignoreDuplicateSlashes option. | |
| Title | @fastify/middie vulnerable to middleware bypass via deprecated ignoreDuplicateSlashes option | |
| Weaknesses | CWE-436 | |
| References |
| |
| Metrics |
cvssV3_1
|
Status: PUBLISHED
Assigner: openjs
Published:
Updated: 2026-04-16T14:41:48.659Z
Reserved: 2026-03-23T19:48:48.714Z
Link: CVE-2026-33804
Updated: 2026-04-16T14:41:41.714Z
Status : Received
Published: 2026-04-16T15:17:34.633
Modified: 2026-04-16T15:17:34.633
Link: CVE-2026-33804
No data.
OpenCVE Enrichment
No data.