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GHSA-wmmm-f939-6g9c
No affected components available
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/*
However, serveStatic may interpret both paths as the same file location (e.g., admin/secret.txt) and return the file.
This inconsistency allows a request such as:
GET //admin/secret.txt
to bypass middleware registered on /admin/* and access protected files.
The issue has been fixed by rejecting paths that contain repeated slashes, ensuring consistent behavior between route matching and static file resolution.
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.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the confidentiality of the information.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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