CVE-2026-35539: Roundcube Webmail

Medium severity, CVSS 6.1. EPSS: 0.4% chance of exploitation in the next 30 days.

An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. XSS exists because of insufficient HTML attachment sanitization in preview mode. A victim must preview a text/html attachment.

Affected products

• Roundcube Webmail: before 1.5.14 (fixed in 1.5.14); from 1.6.0, before 1.6.14 (fixed in 1.6.14)

Published 2026-04-03. Last modified 2026-07-24.