CVSS 4.0
8.2 highCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:NCVE-2026-2880
High (8.2) in fastify fastify\/middie. EPSS 0.4% chance of exploitation in the next 30 days. Fixed in @fastify/middie 9.2.0.
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.
Severity
CVSS 3.1
9.1 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N- EPSS
- 0.4% chance of exploitation in the next 30 days; higher than 37% of CVEs (scores of 2026-10-31)
- CWE
- CWE-20
- Published
- Modified
- Record from
- the NVD, synced
Affected
- fastify:fastify\/middie
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-8p85-9qpw-fwgw | npm | @fastify/middie | <9.2.0 | 9.2.0 |