Description
Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service (multiple-minute daemon hang) via input that is mishandled during hash-table interaction. Because there are many insertions into a single bucket, strcmp becomes slow. This is fixed in 3.4.2, 3.2.8, and 3.0.16.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | cyrus-imapd | 3.4.2-1 | — |
| Debian 13 | cyrus-imapd | 3.4.2-1 | — |
| Debian 12 | cyrus-imapd | 3.4.2-1 | — |
| Debian 9 | cyrus-imapd | 2.5.10-3+deb9u3 | DLA-3052-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | cyrus-imapd-2.4 | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | cyrus-imapd | 3.8.2-1ubuntu0.1~esm1 | USN-7224-1 |
| Ubuntu Pro 22.04 LTS | cyrus-imapd | 3.4.3-3ubuntu0.1+esm1 | USN-7224-1 |
| Ubuntu Pro 20.04 LTS | cyrus-imapd | 3.0.13-5ubuntu0.1~esm1 | USN-7224-1 |
| Ubuntu Pro 18.04 LTS | cyrus-imapd | 2.5.10-3ubuntu1.1+esm1 | USN-7224-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | cyrus-imapd +2 | 3.0.7-20.el8_4.1 | RHSA-2021:3492 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.2 EUS | cyrus-imapd +2 | 3.0.7-16.el8_2.1 | RHSA-2021:3493 |
| RHEL 8.1 EUS | cyrus-imapd +2 | 3.0.7-16.el8_1.1 | RHSA-2021:3546 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | cyrus-imapd | 3.0.7-20.el8_4.1 | RLSA-2021:3492 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | cyrus-imapd | 2.4.22-2.1 | openSUSE-SU-2024:11901-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | cyrus-imapd +2 | 2.4.22-1.amzn2.0.1 | ALAS2-2021-1725 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | cyrus-imapd +2 | 3.0.7-20.el8_4.1 | ELSA-2021-3492 |
Advisories 10
- USN-7224-1 cyrus-imapd vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- DLA-3052-1 cyrus-imapd - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RLSA-2021:3492 Important: cyrus-imapd security update Rocky Linux Security Advisories · Feb 5, 2026
- openSUSE-SU-2024:11901-1 cyradm-2.4.22-2.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- RHSA-2021:3546 Red Hat Security Advisory: cyrus-imapd security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2021:3493 Red Hat Security Advisory: cyrus-imapd security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2021:3492 Red Hat Security Advisory: cyrus-imapd security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- WID-SEC-2022-0389 cyrus imapd: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Jan 23, 2025
- ALAS2-2021-1725 Important: cyrus-imapd security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Dec 9, 2021
- ELSA-2021-3492 Important: cyrus-imapd security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Sep 13, 2021
References
- https://www.cyrusimap.org/imap/download/release-notes/index.html
- https://github.com/cyrusimap/cyrus-imapd/security/advisories
- https://github.com/cyrusimap/cyrus-imapd/commits/master
- https://cyrus.topicbox.com/groups/announce/T3dde0a2352462975-M1386fc44adf967e072f8df13/cyrus-imap-3-4-2-3-2-8-and-3-0-16-released
- FEDORA-2022-c30b1a8aa3 vendor-advisory
- FEDORA-2022-d45bcc5447 vendor-advisory
- [debian-lts-announce] 20220619 [SECURITY] [DLA 3052-1] cyrus-imapd security update mailing-list