The debugger in affected versions of Werkzeug can allow an attacker to execute code on a developer's machine under some circumstances. This requires the attacker to get the developer to interact with a domain and subdomain they control, and enter the debugger PIN, but if they are successful it allows access to the debugger even if it is only running on localhost. This also requires the attacker to guess a URL in the developer's application that will trigger the debugger.
Werkzeug is a comprehensive WSGI web application library. Versions 3.1.5 and below, the safejoin function allows Windows device names as filenames if preceded by other path segments. This was previously reported as GHSA-hgf8-39gv-g3f2, but the added filtering failed to account for the fact that safejoin accepts paths with multiple segments, such as example/NUL. The function sendfromdirectory uses safejoin to safely serve files at user-specified paths under a directory. If the application is running on Windows, and the requested path ends with a special device name, the file will be opened successfully, but reading will hang indefinitely. This issue has been fixed in version 3.1.6.
Pallets Werkzeug is vulnerable to a denial of service, caused by a flaw when parsing multipart/form-data containing a large part with CR/LF character at the beginning. By sending a specially crafted request, a remote authenticated attacker could exploit this vulnerability to cause a denial of service condition.
Applications using Werkzeug to parse multipart/form-data requests are vulnerable to resource exhaustion. A specially crafted form body can bypass the Request.maxformmemorysize setting.
The Request.maxcontentlength setting, as well as resource limits provided by deployment software and platforms, are also available to limit the resources used during a request. This vulnerability does not affect those settings. All three types of limits should be considered and set appropriately when deploying an application.
Werkzeug is a comprehensive WSGI web application library. Prior to version 3.1.4, Werkzeug's safejoin function allows path segments with Windows device names. On Windows, there are special device names such as CON, AUX, etc that are implicitly present and readable in every directory. sendfromdirectory uses safejoin to safely serve files at user-specified paths under a directory. If the application is running on Windows, and the requested path ends with a special device name, the file will be opened successfully, but reading will hang indefinitely. This issue has been patched in version 3.1.4.
Werkzeug is a comprehensive WSGI web application library. Prior to version 3.1.5, Werkzeug's safejoin function allows path segments with Windows device names that have file extensions or trailing spaces. On Windows, there are special device names such as CON, AUX, etc that are implicitly present and readable in every directory. Windows still accepts them with any file extension, such as CON.txt, or trailing spaces such as CON. This issue has been patched in version 3.1.5.
Cross-site scripting (XSS) vulnerability in the renderfull function in debug/tbtools.py in the debugger in Pallets Werkzeug before 0.11.11 (as used in Pallets Flask and other products) allows remote attackers to inject arbitrary web script or HTML via a field that contains an exception message.