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5.3
Repeated slashes in URL can bypass security restrictions in Node.js server
GHSA-92pp-h63x-v22m
CVE-2026-39406
Summary
A security risk exists in Node.js servers using the serveStatic middleware. If an attacker uses repeated slashes in a URL, they may be able to access files that are intended to be protected by security controls. This can happen if your server uses both serveStatic and route-based middleware for access control. To fix this, review your server configuration and ensure that you're not relying on the serveStatic middleware to handle sensitive files.
What to do
- Update hono node-server to version 1.19.13.
Affected software
| Vendor | Product | Affected versions | Fix available |
|---|---|---|---|
| hono | node-server | <= 1.19.13 | 1.19.13 |
Original title
@hono/node-server: Middleware bypass via repeated slashes in serveStatic
Original description
## Summary
A path handling inconsistency in `serveStatic` allows protected static files to be accessed by using repeated slashes (`//`) in the request path.
When route-based middleware (e.g., `/admin/*`) is used for authorization, the router may not match paths containing repeated slashes, while `serveStatic` resolves them as normalized paths. This can lead to a middleware bypass.
## Details
The routing layer and `serveStatic` handle repeated slashes differently.
For example:
- `/admin/secret.txt` => matches `/admin/*`
- `//admin/secret.txt` => may not match `/admin/*`
This inconsistency allows a request such as:
```
GET //admin/secret.txt
```
to bypass middleware registered on `/admin/*` and access protected files.
## Impact
An attacker can access static files that are intended to be protected by route-based middleware by using repeated slashes in the request path.
This can lead to unauthorized access to sensitive files under the static root.
This issue affects applications that rely on `serveStatic` together with route-based middleware for access control.
A path handling inconsistency in `serveStatic` allows protected static files to be accessed by using repeated slashes (`//`) in the request path.
When route-based middleware (e.g., `/admin/*`) is used for authorization, the router may not match paths containing repeated slashes, while `serveStatic` resolves them as normalized paths. This can lead to a middleware bypass.
## Details
The routing layer and `serveStatic` handle repeated slashes differently.
For example:
- `/admin/secret.txt` => matches `/admin/*`
- `//admin/secret.txt` => may not match `/admin/*`
This inconsistency allows a request such as:
```
GET //admin/secret.txt
```
to bypass middleware registered on `/admin/*` and access protected files.
## Impact
An attacker can access static files that are intended to be protected by route-based middleware by using repeated slashes in the request path.
This can lead to unauthorized access to sensitive files under the static root.
This issue affects applications that rely on `serveStatic` together with route-based middleware for access control.
ghsa CVSS3.1
5.3
Vulnerability type
CWE-22
Path Traversal
Published: 8 Apr 2026 · Updated: 8 Apr 2026 · First seen: 8 Apr 2026