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Cyrus IMAP

Scalable IMAP and POP server for large deployments

Mail Servers ★ 652 stars Hard setup BSD-3-Clause

Cyrus IMAP is an enterprise-grade mail server designed to scale to very large numbers of mailboxes, with its own optimized mail store. It supports IMAP, POP, JMAP, and server-side search.

Official siteSource code

Key features

  • Scales to many mailboxes
  • Optimized mail store
  • JMAP and IMAP support
  • Server-side search

Strengths

  • Released under the BSD-3-Clause license
  • Written in C

Is Cyrus IMAP secure?

No known vulnerabilities affect Cyrus IMAP's latest release (cyrus-imapd-3.12.4). OSV.dev lists 13 past advisories for the project; none of them applies to this release. No known vulnerabilities is not proof of security: it means none have been publicly catalogued.

  • Most recent fixed advisory CVE-2026-61911, published 2026-09-09 (35 days ago), fixed in 3.8.8, 3.10.4, 3.12.4

Source: OSV.dev, checked 2026-10-14. How this is measured.

Cyrus IMAP replaces

Self-hosted Microsoft Exchange alternatives

Health badge

Maintain Cyrus IMAP? Add its health score to your README. The badge links back to this page.

SelfHostIndex: 84 · excellent

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[![SelfHostIndex health score for Cyrus IMAP](https://selfhostindex.com/badge/cyrus-imapd.svg)](https://selfhostindex.com/app/cyrus-imapd/)
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<a href="https://selfhostindex.com/app/cyrus-imapd/"><img src="https://selfhostindex.com/badge/cyrus-imapd.svg" alt="SelfHostIndex health score for Cyrus IMAP"></a>
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.. image:: https://selfhostindex.com/badge/cyrus-imapd.svg
   :alt: SelfHostIndex health score for Cyrus IMAP
   :target: https://selfhostindex.com/app/cyrus-imapd/

The score is recomputed on every nightly rebuild from public repository data — see how it is calculated.

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