CVE-2026-74998 [HIGH] – In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, responses from the CSS (Cascadi

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, responses from the CSS (Cascading Style Sheets) proxy were not validated, which may result in information disclosure or XSS (cross-site scripting) via MIME sniffing.