On Python < 3.11 on Windows, os.path.isabs() does not catch UNC paths like //server/share. Werkzeug's safe_join() relies on this check, and so can produce a path that is not safe, potentially allowing unintended access to data. Applications using Python >= 3.11, or not using Windows, are not vulnerable.
Applications using Werkzeug to parse multipart/form-data requests are vulnerable to resource exhaustion. A specially crafted form body can bypass the Request.max_form_memory_size setting. The Request.max_content_length 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.
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 …
Werkzeug multipart data parser needs to find a boundary that may be between consecutive chunks. That's why parsing is based on looking for newline characters. Unfortunately, code looking for partial boundary in the buffer is written inefficiently, so if we upload a file that starts with CR or LF and then is followed by megabytes of data without these characters: all of these bytes are appended chunk by chunk into …
Browsers may allow "nameless" cookies that look like =value instead of key=value. A vulnerable browser may allow a compromised application on an adjacent subdomain to exploit this to set a cookie like =__Host-test=bad for another subdomain. Werkzeug <= 2.2.2 will parse the cookie =__Host-test=bad as __Host-test=bad. If a Werkzeug application is running next to a vulnerable or malicious subdomain which sets such a cookie using a vulnerable browser, the Werkzeug …
Werkzeug's multipart form data parser will parse an unlimited number of parts, including file parts. Parts can be a small amount of bytes, but each requires CPU time to parse and may use more memory as Python data. If a request can be made to an endpoint that accesses request.data, request.form, request.files, or request.get_data(parse_form_data=False), it can cause unexpectedly high resource usage. This allows an attacker to cause a denial of …
Improper parsing of HTTP requests in Pallets Werkzeug v2.1.0 and below allows attackers to perform HTTP Request Smuggling using a crafted HTTP request with multiple requests included inside the body. NOTE: the vendor's position is that this behavior can only occur in unsupported configurations involving development mode and an HTTP server from outside the Werkzeug project
Cross-site scripting (XSS) vulnerability in the render_full 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.
Open redirect vulnerability in werkzeug before 0.11.6 via a double slash in the URL.
Pallets Werkzeug before 0.15.3, when used with Docker, has insufficient debugger PIN randomness because Docker containers share the same machine id.
In Pallets Werkzeug, SharedDataMiddleware mishandles drive names (such as C:) in Windows pathnames.