Proton Bridge vs Roundcube

Every release in this window is a security update, and they arrive in matched pairs — the same fix set landed on the 1.7 stable branch and backported to the 1.6 LTS branch minutes apart. The August pair closes eleven reported issues, including remote code execution through the markasjunk plugin's cmd_learn driver, IMAP command injection via LITERAL+ byte-count desynchronization, LDAP filter injection through unescaped substitution in search_filter, arbitrary Sieve script injection past managesieve_disabled_actions, multiple SSRF filter bypasses, and stored XSS. The June and July pairs follow the same structure with different findings.

Roundcube is absorbing sustained external security-research attention and has settled into a repeatable response cadence: fix, pair the branches, ship. The recurring categories are telling — HTML and CSS sanitizer bypasses via SVG attributes, SSRF filters defeated by address-space and hostname tricks, and injection through plugin drivers — which means the same attack surfaces keep yielding new variants rather than being closed once. The 1.5 branch received its last pair in March; since 1.7.0 arrived in May, maintenance has narrowed to two branches instead of three.

Expect the next release to be another 1.7/1.6 security pair rather than a feature drop, and to include further sanitizer or URL-fetch bypass fixes, since those two categories have recurred in every pair in this window.