CVE-2023-23934

A flaw was found in python-werkzeug. Browsers may allow "nameless" cookies 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 for another subdomain. If a Werkzeug application is running next to a vulnerable or malicious subdomain that sets such a cookie using a vulnerable browser, the Werkzeug application will see the bad cookie value but the valid cookie key.

It was discovered that Werkzeug did not properly handle the parsing of nameless cookies. A remote attacker could possibly use this issue to shadow other cookies. It was discovered that Werkzeug could be made to process unlimited number of multipart form data parts. A remote attacker could possibly use this issue to cause Werkzeug to consume resources, leading to a denial of service.