We just published security updates to the 1.6 and 1.5 LTS versions of Roundcube Webmail. They both contain a fix for recently reported security vulnerability.
Security fixes
Fix Post-Auth RCE via PHP Object Deserialization reported by firs0v.
See the full changelogs in the release notes on the Github download pages for the updated versions 1.6.11 (https://github.com/roundcube/roundcubemail/releases/tag/1.6.11) and 1.5.10 (https://github.com/roundcube/roundcubemail/releases/tag/1.5.10).
We strongly recommend to update all productive installations of Roundcube 1.6.x and 1.5.x with this new versions.
Source: https://roundcube.net/news/2025/06/01/security-updates-1.6.11-and-1.5.10
Get it Now: https://roundcube.net/download