@fastify/express v4.0.4 and earlier contains a path handling bug in the onRegister function that causes middleware paths to be doubled when inherited by child plugins. When a child plugin is registered with a prefix that matches a middleware path, the middleware path is prefixed a second time, causing it to never match incoming requests. This results in complete bypass of Express middleware security controls, including authentication, authorization, and rate limiting, for all routes defined within affected child plugin scopes. No special configuration or request crafting is required.
Upgrade to @fastify/express v4.0.5 or later.
References
| Link | Resource |
|---|---|
| https://cna.openjsf.org/security-advisories.html | Vendor Advisory |
| https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c | Exploit Mitigation Vendor Advisory |
| https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c | Exploit Mitigation Vendor Advisory |
Configurations
History
01 Jun 2026, 15:29
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:a:fastify:fastify\/express:*:*:*:*:*:node.js:*:* | |
| First Time |
Fastify
Fastify fastify\/express |
|
| References | () https://cna.openjsf.org/security-advisories.html - Vendor Advisory | |
| References | () https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c - Exploit, Mitigation, Vendor Advisory |
15 Apr 2026, 14:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-04-15 10:16
Updated : 2026-06-01 15:29
NVD link : CVE-2026-33807
Mitre link : CVE-2026-33807
CVE.ORG link : CVE-2026-33807
JSON object : View
Products Affected
fastify
- fastify\/express
CWE
CWE-436
Interpretation Conflict