CVE Explorer
CVE-2026-33807
@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 with
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"defaultStatus":"unaffected","packageURL":"pkg:npm/@fastify/express","product":"@fastify/express","vendor":"fastify","versions":[{"lessThan":"4.0.5","status":"affected","version":"0","versionType":"semver"},{"status":"unaffected","version":"4.0.5","versionType":"semver"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:bdb281bf4194ddf4a02a531c8d7e0888aaa43a23b371a270df1037acbd768960 · sha256:ff80458cf875d416… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":9.1,"baseSeverity":"CRITICAL","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:bdb281bf4194ddf4a02a531c8d7e0888aaa43a23b371a270df1037acbd768960 · sha256:ff80458cf875d416… · /containers/cna/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-436","description":"CWE-436: Interpretation Conflict","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:bdb281bf4194ddf4a02a531c8d7e0888aaa43a23b371a270df1037acbd768960 · sha256:ff80458cf875d416… · /containers/cna/problemTypes/0/descriptions/0
Source references
3 source assertions{"url":"https://cna.openjsf.org/security-advisories.html"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:bdb281bf4194ddf4a02a531c8d7e0888aaa43a23b371a270df1037acbd768960 · sha256:ff80458cf875d416… · /containers/cna/references/1
{"url":"https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:bdb281bf4194ddf4a02a531c8d7e0888aaa43a23b371a270df1037acbd768960 · sha256:ff80458cf875d416… · /containers/cna/references/0
{"tags":["exploit"],"url":"https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:bdb281bf4194ddf4a02a531c8d7e0888aaa43a23b371a270df1037acbd768960 · sha256:ff80458cf875d416… · /containers/adp/0/references/0
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.