NanoMQ
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Comparison · Comms
Roundcube vs Gromox
A side-by-side editorial comparison of Roundcube and Gromox — release velocity, themes, recent moves, and the top alternatives to consider.
Roundcube vs Gromox: at a glance
What is Roundcube?
Roundcube is shipping matched security pairs across 1.7 and 1.6 LTS, roughly monthly.
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.
What is Gromox?
Gromox is filling in Exchange Web Services fast enough to matter for non-Outlook clients.
Gromox ships a minor roughly every four to eight weeks and has moved from 3.0 to 3.9 in this window. The centre of gravity is EWS: 3.6 landed roughly two dozen operations at once — task CRUD, delegate management, calendar occurrences with timezones, full meeting invitation and cancellation lifecycle, read receipts — and every release since has extended or corrected it. Alongside that, 3.8 introduced a per-store split-process model for the Information Store and partial IMAP4rev2 support, and 3.9 made auto-accepted room bookings send confirmations and handle cancellations.
Roundcube vs Gromox: editorial side-by-side
Roundcube
5.0COMMS
Roundcube is shipping matched security pairs across 1.7 and 1.6 LTS, roughly monthly.
◆ Current state
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.
◆ Where it's heading
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.
◆ Prediction
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.
Gromox
2.5COMMS
Gromox is filling in Exchange Web Services fast enough to matter for non-Outlook clients.
◆ Current state
Gromox ships a minor roughly every four to eight weeks and has moved from 3.0 to 3.9 in this window. The centre of gravity is EWS: 3.6 landed roughly two dozen operations at once — task CRUD, delegate management, calendar occurrences with timezones, full meeting invitation and cancellation lifecycle, read receipts — and every release since has extended or corrected it. Alongside that, 3.8 introduced a per-store split-process model for the Information Store and partial IMAP4rev2 support, and 3.9 made auto-accepted room bookings send confirmations and handle cancellations.
◆ Where it's heading
The project is working outward from MAPI compatibility toward the protocols that non-Outlook clients actually speak. EWS is the clearest case, but the same pattern shows in IMAP (custom keywords, IMAP4rev2 commands, SENT* keywords fixed to test the Date header as the spec requires) and in AutoDiscover fixes that unblocked Thunderbird. A second, quieter thread is offloading format conversion to external tools — Pandoc for HTML/RTF, Chawan for HTML-to-text — rather than maintaining converters in-tree. Meeting and calendar handling generates the most fix traffic, which is what you would expect from the hardest part of an Exchange-compatible server.
◆ Prediction
Expect EWS coverage to keep expanding toward whatever operations remain unimplemented, since that has been the consistent destination of feature work for five releases. The split-process Information Store introduced in 3.8 is the other thread to watch — a config bitmask suggests further isolation work is planned rather than finished.
Alternatives to Roundcube and Gromox
Other Comms products tracked by Sparkpulse, ranked by recent ship velocity. Each card links to a full editorial trajectory and lets you pivot into a head-to-head comparison with either Roundcube or Gromox.
Heymarket
Real features ship between the SEO posts: tags, webhooks, escalations, and now RCS via Twilio.
Elastic Email
A competitor-comparison mill that quietly shipped a DMARC monitoring tool
Notion
Notion is building the place where other companies' agents come to work
Twilio
Twilio is closing gaps: email deliverability controls, WhatsApp parity, and regional network plumbing.
Bandwidth
Coverage, quality metrics and self-service — Bandwidth is closing the gaps enterprises audit it on.
See all Roundcube alternatives → · See all Gromox alternatives →
Recent activity from Roundcube and Gromox
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 8h agoRoundcube1.7.3 fixes 11 issues including plugin RCE and IMAP injection
- 8h agoRoundcube1.6.18 backports the same 11 security fixes to the LTS branch
- 16d agoGromox3.9 makes room bookings and EWS meetings properly actionable
- 1mo agoRoundcube1.6.17 fixes CVE-2026-54432/54433 and a TNEF decoder loop
- 1mo agoRoundcube1.7.2 ships July's security set to the stable branch
- 1mo agoGromox3.8 splits the Information Store per store and extends IMAP
- 1mo agoRoundcube1.6.16 fixes pre-auth SQL injection and arbitrary file delete
- 1mo agoRoundcube1.7.1 pairs June's fixes with Enigma HKP key lookup
- 3mo agoGromox3.7 fixes shared calendars, EWS fields and Thunderbird discovery
- 4mo agoGromox3.6 lands the full EWS meeting, delegate and task surface ⚡
- 5mo agoGromox3.5 adds per-service listen directives and fixes notifications
- 6mo agoGromox3.4 adds pre-delivery junk shelving and tightens header handling
Frequently asked questions
What is the difference between Roundcube and Gromox?
They serve adjacent needs but don't currently overlap on shipped themes. Roundcube is currently shipping more aggressively (velocity 5.0 vs 2.5), with 0 editorial sparks in the last 30 days against 0. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is Roundcube better than Gromox?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Roundcube is currently shipping more aggressively (velocity 5.0 vs 2.5), with 0 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other Comms products to evaluate alongside.
What are the best alternatives to Roundcube?
Top Roundcube alternatives in Comms are ranked by recent ship velocity. Browse the "Roundcube alternatives" section above for the current picks, or visit /alternatives/roundcube for the full list with editorial commentary on each.
What are the best alternatives to Gromox?
Top Gromox alternatives in Comms are ranked by recent ship velocity. Browse the "Gromox alternatives" section above for the current picks, or visit /alternatives/gromox for the full list with editorial commentary on each.