CVE-2026-35537: Roundcube Webmail

High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 30 days.

An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Unsafe deserialization in the redis/memcache session handler may lead to arbitrary file write operations by unauthenticated attackers via crafted session data.

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.