CVE-2026-42391
Fixed in a distro release EPSS <1%CVSS 7.5
An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by the same process. This can cause degradation or denial of service for IMAP logins. Limit the number of connections handled by a single imap-login process. This has a performance impact though. Update to non-vulnerable version. No publicly available exploits are known.
Products: Open-Xchange GmbH OX Dovecot Pro, Open-Xchange GmbH OX Dovecot CE
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| AlmaLinux 10 | dovecot | 1:2.3.21-19.el10_2.8 |
| AlmaLinux 10 | dovecot-devel | 1:2.3.21-19.el10_2.8 |
| AlmaLinux 10 | dovecot-mysql | 1:2.3.21-19.el10_2.8 |
| AlmaLinux 10 | dovecot-pgsql | 1:2.3.21-19.el10_2.8 |
| AlmaLinux 10 | dovecot-pigeonhole | 1:2.3.21-19.el10_2.8 |
| AlmaLinux 8 | dovecot | 1:2.3.16-16.el8_10 |
| AlmaLinux 8 | dovecot-devel | 1:2.3.16-16.el8_10 |
| AlmaLinux 8 | dovecot-mysql | 1:2.3.16-16.el8_10 |
| AlmaLinux 8 | dovecot-pgsql | 1:2.3.16-16.el8_10 |
| AlmaLinux 8 | dovecot-pigeonhole | 1:2.3.16-16.el8_10 |
| AlmaLinux 9 | dovecot | 1:2.3.16-18.el9_8.8 |
| AlmaLinux 9 | dovecot-devel | 1:2.3.16-18.el9_8.8 |
| AlmaLinux 9 | dovecot-mysql | 1:2.3.16-18.el9_8.8 |
| AlmaLinux 9 | dovecot-pgsql | 1:2.3.16-18.el9_8.8 |
| AlmaLinux 9 | dovecot-pigeonhole | 1:2.3.16-18.el9_8.8 |
| Alpine 3.23 | dovecot | 2.4.5-r0 |
| Alpine 3.24 | dovecot | 2.4.5-r0 |
| Amazon Linux 2 | dovecot | 1:2.2.36-6.amzn2.1.4 |
| Amazon Linux 2 | dovecot-devel | 1:2.2.36-6.amzn2.1.4 |
| Amazon Linux 2 | dovecot-mysql | 1:2.2.36-6.amzn2.1.4 |
| Amazon Linux 2 | dovecot-pgsql | 1:2.2.36-6.amzn2.1.4 |
| Amazon Linux 2 | dovecot-pigeonhole | 1:2.2.36-6.amzn2.1.4 |
| Amazon Linux 2023 | dovecot | 1:2.3.20-1.amzn2023.0.4 |
| Amazon Linux 2023 | dovecot-devel | 1:2.3.20-1.amzn2023.0.4 |
| Amazon Linux 2023 | dovecot-mysql | 1:2.3.20-1.amzn2023.0.4 |
| Amazon Linux 2023 | dovecot-pgsql | 1:2.3.20-1.amzn2023.0.4 |
| Amazon Linux 2023 | dovecot-pigeonhole | 1:2.3.20-1.amzn2023.0.4 |
| Debian 12 | dovecot | no fix |
| Debian 13 | dovecot | 1:2.4.1+dfsg1-6+deb13u7 |
| Debian 14 | dovecot | 1:2.4.5+dfsg1-1 |
| Red Hat Enterprise Linux 10.2 | dovecot | 1:2.3.21-19.el10_2.8 |
| Red Hat Enterprise Linux 10.2 | dovecot-debuginfo | 1:2.3.21-19.el10_2.8 |
| Red Hat Enterprise Linux 10.2 | dovecot-debugsource | 1:2.3.21-19.el10_2.8 |
| Red Hat Enterprise Linux 10.2 | dovecot-devel | 1:2.3.21-19.el10_2.8 |
| Red Hat Enterprise Linux 10.2 | dovecot-mysql | 1:2.3.21-19.el10_2.8 |
| Red Hat Enterprise Linux 10.2 | dovecot-mysql-debuginfo | 1:2.3.21-19.el10_2.8 |
| Red Hat Enterprise Linux 10.2 | dovecot-pgsql | 1:2.3.21-19.el10_2.8 |
| Red Hat Enterprise Linux 10.2 | dovecot-pgsql-debuginfo | 1:2.3.21-19.el10_2.8 |
| Red Hat Enterprise Linux 10.2 | dovecot-pigeonhole | 1:2.3.21-19.el10_2.8 |
| Red Hat Enterprise Linux 10.2 | dovecot-pigeonhole-debuginfo | 1:2.3.21-19.el10_2.8 |
| Red Hat Enterprise Linux 8 | dovecot | 1:2.3.16-16.el8_10 |
| Red Hat Enterprise Linux 8 | dovecot-debuginfo | 1:2.3.16-16.el8_10 |
| Red Hat Enterprise Linux 8 | dovecot-debugsource | 1:2.3.16-16.el8_10 |
| Red Hat Enterprise Linux 8 | dovecot-devel | 1:2.3.16-16.el8_10 |
| Red Hat Enterprise Linux 8 | dovecot-mysql | 1:2.3.16-16.el8_10 |
| Red Hat Enterprise Linux 8 | dovecot-mysql-debuginfo | 1:2.3.16-16.el8_10 |
| Red Hat Enterprise Linux 8 | dovecot-pgsql | 1:2.3.16-16.el8_10 |
| Red Hat Enterprise Linux 8 | dovecot-pgsql-debuginfo | 1:2.3.16-16.el8_10 |
| Red Hat Enterprise Linux 8 | dovecot-pigeonhole | 1:2.3.16-16.el8_10 |
| Red Hat Enterprise Linux 8 | dovecot-pigeonhole-debuginfo | 1:2.3.16-16.el8_10 |
| Red Hat Enterprise Linux 9 | dovecot | 1:2.3.16-18.el9_8.8 |
| Red Hat Enterprise Linux 9 | dovecot-debuginfo | 1:2.3.16-18.el9_8.8 |
| Red Hat Enterprise Linux 9 | dovecot-debugsource | 1:2.3.16-18.el9_8.8 |
| Red Hat Enterprise Linux 9 | dovecot-devel | 1:2.3.16-18.el9_8.8 |
| Red Hat Enterprise Linux 9 | dovecot-mysql | 1:2.3.16-18.el9_8.8 |
| Red Hat Enterprise Linux 9 | dovecot-mysql-debuginfo | 1:2.3.16-18.el9_8.8 |
| Red Hat Enterprise Linux 9 | dovecot-pgsql | 1:2.3.16-18.el9_8.8 |
| Red Hat Enterprise Linux 9 | dovecot-pgsql-debuginfo | 1:2.3.16-18.el9_8.8 |
| Red Hat Enterprise Linux 9 | dovecot-pigeonhole | 1:2.3.16-18.el9_8.8 |
| Red Hat Enterprise Linux 9 | dovecot-pigeonhole-debuginfo | 1:2.3.16-18.el9_8.8 |
| Rocky Linux 10 | dovecot | 1:2.3.21-19.el10_2.8 |
| Rocky Linux 8 | dovecot | 1:2.3.16-16.el8_10 |
| Rocky Linux 9 | dovecot | 1:2.3.16-18.el9_8.8 |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Module for Server Applications 15 SP7 | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server 12 SP5-LTSS | dovecot22 | 2.2.31-19.40.1 |
| SUSE Linux Enterprise Server 15 SP4-LTSS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server 15 SP5-LTSS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server 15 SP6-LTSS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server 16.0 | dovecot24 | 2.4.4-160000.2.1 |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | dovecot22 | 2.2.31-19.40.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server for SAP applications 16.0 | dovecot24 | 2.4.4-160000.2.1 |
| Ubuntu 16.04 LTS | dovecot | no fix |
| Ubuntu 18.04 LTS | dovecot | no fix |
| Ubuntu 20.04 LTS | dovecot | no fix |
| Ubuntu 22.04 LTS | dovecot | no fix |
| Ubuntu 24.04 LTS | dovecot | no fix |
| Ubuntu 26.04 LTS | dovecot | no fix |
| Ubuntu Pro 14.04 LTS | dovecot | no fix |
| openSUSE Leap 16.0 | dovecot24 | 2.4.4-160000.2.1 |
| openSUSE Tumbleweed | dovecot24 | 2.4.5-1.1 |