CVE-2025-8037: firefox: thunderbird: Nameless cookies shadow secure cookies

Severity: Critical

CVSS Score: 9.1

Setting a nameless cookie with an equals sign in the value shadowed other cookies. Even if the nameless cookie was set over HTTP and the shadowed cookie included the `Secure` attribute. This vulnerability affects Firefox < 141, Firefox ESR < 140.1, Thunderbird < 141, and Thunderbird < 140.1.