CVE-2026-75006: Roundcube Webmail

Medium severity, CVSS 5.8. EPSS: 0.4% chance of exploitation in the next 30 days.

In Roundcube Webmail before 1.6.18 and 1.7.x before 1.7.3, insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to SSRF or Information Disclosure, e.g., if stylesheet links point to local network hosts. This issue exists because of insufficient fixes for CVE-2026-35540, CVE-2026-48843 and CVE-2026-62643.

Affected products

• Roundcube Webmail: from 1.6.0, before 1.6.18 (fixed in 1.6.18); from 1.7.0, before 1.7.3 (fixed in 1.7.3)

Published 2026-08-17. Last modified 2026-09-08.