CVE-2023-23934

Name of the Vulnerable Software and Affected Versions Werkzeug versions prior to 2.2.3

Description The issue is related to how Werkzeug handles "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 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 application will see the bad cookie value but the valid cookie key.

Recommendations For Werkzeug versions prior to 2.2.3, update to version 2.2.3 to resolve the issue. As a temporary workaround, consider restricting access to the vulnerable subdomain to minimize the risk of exploitation. Avoid using vulnerable browsers that allow "nameless" cookies.