CVE-2026-39406

@hono/node-server has a middleware bypass via repeated slashes in serveStatic

CVSS 3.1 5.3 MEDIUMEUVD CVSS 3.1 5.3 CVSS 3.1 · [email protected] · Secondary 5.3 MEDIUMCVSS_V3 Publisher rating MODERATEFixed by @hono/node-server 1.19.13KEV status unknown

Original advisory

cve-program · CVE-2026-39406

Published

@hono/node-server allows running the Hono application on Node.js. Prior to 1.19.13, 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. This vulnerability is fixed in 1.19.13.

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euvd · EUVD-2026-20491

Published

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nvd · CVE-2026-39406

Published

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osv · GHSA-92pp-h63x-v22m

Published

## 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.

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Affected versions, risk and source history

Exploitation and risk

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Advisory history

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15 Nov 2026 11:06:11 UTC