# CVE-2026-33605: dovecot: An unauthenticated attacker can crash the ManageSieve login process by sending a small malformed command before authe...

CVE-2026-33605 is fixed in 12 products on 1 platform, first by RHSA-2026:79371, released August 28, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-33605
- Priority: High
- CVSS: 9.1 (important)
- EPSS: 0.0045
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 28, 2026

## Description

An unauthenticated attacker can crash the ManageSieve login process by sending a small malformed command before authenticating. If running in high-security mode (default for community releases), only the attacker's own connection is terminated. If running in high-performance mode (default for Pro releases), all connections handled by the same managesieve-login process are terminated. Repeating the attack can cause denial of service for Sieve script management. Restrict network access to the ManageSieve service to trusted clients. Update to non-vulnerable version. No publicly available exploits are known.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | dovecot Debian 12.15 (bookworm) | 1:2.3.19.1+dfsg1-2.1+deb12u7 | [DEBIAN-CVE-2026-33605](https://patchblox.com/security/data/fix/linux/debian-cve-2026-33605.md) | Sep 10, 2026 |
| Linux | dovecot Debian 13.5 (trixie) | 1:2.4.1+dfsg1-6+deb13u7 | [DEBIAN-CVE-2026-33605](https://patchblox.com/security/data/fix/linux/debian-cve-2026-33605.md) | Sep 10, 2026 |
| Linux | dovecot Debian 14 | 1:2.4.5+dfsg1-1 | [DEBIAN-CVE-2026-33605](https://patchblox.com/security/data/fix/linux/debian-cve-2026-33605.md) | Sep 10, 2026 |
| Linux | dovecot Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot RHEL 10 | 2.3.21-19.el10_2.8 | [RHSA-2026:79371](https://patchblox.com/security/data/fix/linux/rhsa-2026-79371.md) | Aug 28, 2026 |
| Linux | dovecot RHEL 8 | 1:2.3.16-16.el8_10 | [RHSA-2026:76763](https://patchblox.com/security/data/fix/linux/rhsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot RHEL 9 | 1:2.3.16-18.el9_8.8 | [RHSA-2026:80825](https://patchblox.com/security/data/fix/linux/rhsa-2026-80825.md) | Oct 13, 2026 |
| Linux | dovecot almalinux 10 | 1:2.3.21-19.el10_2.8 | [ALSA-2026:79371](https://patchblox.com/security/data/fix/linux/alsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot almalinux 8 | 1:2.3.16-16.el8_10 | [ALSA-2026:76763](https://patchblox.com/security/data/fix/linux/alsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot almalinux 9 | 1:2.3.16-18.el9_8.8 | [ALSA-2026:80825](https://patchblox.com/security/data/fix/linux/alsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot ol 10 | 1:2.3.21-19.el10_2.8 | [ELSA-2026-79371](https://patchblox.com/security/data/fix/linux/elsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot ol 8 | 1:2.3.16-16.el8_10 | [ELSA-2026-76763](https://patchblox.com/security/data/fix/linux/elsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot ol 9 | 1:2.3.16-18.el9_8.8 | [ELSA-2026-80825](https://patchblox.com/security/data/fix/linux/elsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot rocky 10 | 1:2.3.21-19.el10_2.8 | [RLSA-2026:79371](https://patchblox.com/security/data/fix/linux/rlsa-2026-79371.md) | Nov 7, 2026 |
| Linux | dovecot rocky 8 | 1:2.3.16-16.el8_10 | [RLSA-2026:76763](https://patchblox.com/security/data/fix/linux/rlsa-2026-76763.md) | Oct 7, 2026 |
| Linux | dovecot rocky 9 | 1:2.3.16-18.el9_8.8 | [RLSA-2026:80825](https://patchblox.com/security/data/fix/linux/rlsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-debuginfo Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-debugsource Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-devel Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-devel RHEL 8 | 1:2.3.16-16.el8_10 | [RHSA-2026:76763](https://patchblox.com/security/data/fix/linux/rhsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-devel RHEL 9 | 1:2.3.16-18.el9_8.8 | [RHSA-2026:80825](https://patchblox.com/security/data/fix/linux/rhsa-2026-80825.md) | Oct 13, 2026 |
| Linux | dovecot-devel almalinux 10 | 1:2.3.21-19.el10_2.8 | [ALSA-2026:79371](https://patchblox.com/security/data/fix/linux/alsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-devel almalinux 8 | 1:2.3.16-16.el8_10 | [ALSA-2026:76763](https://patchblox.com/security/data/fix/linux/alsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-devel almalinux 9 | 1:2.3.16-18.el9_8.8 | [ALSA-2026:80825](https://patchblox.com/security/data/fix/linux/alsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-devel ol 10 | 1:2.3.21-19.el10_2.8 | [ELSA-2026-79371](https://patchblox.com/security/data/fix/linux/elsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-devel ol 8 | 1:2.3.16-16.el8_10 | [ELSA-2026-76763](https://patchblox.com/security/data/fix/linux/elsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-devel ol 9 | 1:2.3.16-18.el9_8.8 | [ELSA-2026-80825](https://patchblox.com/security/data/fix/linux/elsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-mysql Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-mysql RHEL 8 | 1:2.3.16-16.el8_10 | [RHSA-2026:76763](https://patchblox.com/security/data/fix/linux/rhsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-mysql RHEL 9 | 1:2.3.16-18.el9_8.8 | [RHSA-2026:80825](https://patchblox.com/security/data/fix/linux/rhsa-2026-80825.md) | Oct 13, 2026 |
| Linux | dovecot-mysql almalinux 10 | 1:2.3.21-19.el10_2.8 | [ALSA-2026:79371](https://patchblox.com/security/data/fix/linux/alsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-mysql almalinux 8 | 1:2.3.16-16.el8_10 | [ALSA-2026:76763](https://patchblox.com/security/data/fix/linux/alsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-mysql almalinux 9 | 1:2.3.16-18.el9_8.8 | [ALSA-2026:80825](https://patchblox.com/security/data/fix/linux/alsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-mysql ol 10 | 1:2.3.21-19.el10_2.8 | [ELSA-2026-79371](https://patchblox.com/security/data/fix/linux/elsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-mysql ol 8 | 1:2.3.16-16.el8_10 | [ELSA-2026-76763](https://patchblox.com/security/data/fix/linux/elsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-mysql ol 9 | 1:2.3.16-18.el9_8.8 | [ELSA-2026-80825](https://patchblox.com/security/data/fix/linux/elsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-mysql-debuginfo Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-pgsql Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-pgsql RHEL 8 | 1:2.3.16-16.el8_10 | [RHSA-2026:76763](https://patchblox.com/security/data/fix/linux/rhsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-pgsql RHEL 9 | 1:2.3.16-18.el9_8.8 | [RHSA-2026:80825](https://patchblox.com/security/data/fix/linux/rhsa-2026-80825.md) | Oct 13, 2026 |
| Linux | dovecot-pgsql almalinux 10 | 1:2.3.21-19.el10_2.8 | [ALSA-2026:79371](https://patchblox.com/security/data/fix/linux/alsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-pgsql almalinux 8 | 1:2.3.16-16.el8_10 | [ALSA-2026:76763](https://patchblox.com/security/data/fix/linux/alsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-pgsql almalinux 9 | 1:2.3.16-18.el9_8.8 | [ALSA-2026:80825](https://patchblox.com/security/data/fix/linux/alsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-pgsql ol 10 | 1:2.3.21-19.el10_2.8 | [ELSA-2026-79371](https://patchblox.com/security/data/fix/linux/elsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-pgsql ol 8 | 1:2.3.16-16.el8_10 | [ELSA-2026-76763](https://patchblox.com/security/data/fix/linux/elsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-pgsql ol 9 | 1:2.3.16-18.el9_8.8 | [ELSA-2026-80825](https://patchblox.com/security/data/fix/linux/elsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-pgsql-debuginfo Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-pigeonhole Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot-pigeonhole RHEL 8 | 1:2.3.16-16.el8_10 | [RHSA-2026:76763](https://patchblox.com/security/data/fix/linux/rhsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-pigeonhole RHEL 9 | 1:2.3.16-18.el9_8.8 | [RHSA-2026:80825](https://patchblox.com/security/data/fix/linux/rhsa-2026-80825.md) | Oct 13, 2026 |
| Linux | dovecot-pigeonhole almalinux 10 | 1:2.3.21-19.el10_2.8 | [ALSA-2026:79371](https://patchblox.com/security/data/fix/linux/alsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-pigeonhole almalinux 8 | 1:2.3.16-16.el8_10 | [ALSA-2026:76763](https://patchblox.com/security/data/fix/linux/alsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-pigeonhole almalinux 9 | 1:2.3.16-18.el9_8.8 | [ALSA-2026:80825](https://patchblox.com/security/data/fix/linux/alsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-pigeonhole ol 10 | 1:2.3.21-19.el10_2.8 | [ELSA-2026-79371](https://patchblox.com/security/data/fix/linux/elsa-2026-79371.md) | Oct 8, 2026 |
| Linux | dovecot-pigeonhole ol 8 | 1:2.3.16-16.el8_10 | [ELSA-2026-76763](https://patchblox.com/security/data/fix/linux/elsa-2026-76763.md) | Oct 6, 2026 |
| Linux | dovecot-pigeonhole ol 9 | 1:2.3.16-18.el9_8.8 | [ELSA-2026-80825](https://patchblox.com/security/data/fix/linux/elsa-2026-80825.md) | Nov 7, 2026 |
| Linux | dovecot-pigeonhole-debuginfo Fedora 43 | 1:2.4.5-1.fc43 | [FEDORA-2026-E8A6485109](https://patchblox.com/security/data/fix/linux/fedora-2026-e8a6485109.md) | Sep 10, 2026 |
| Linux | dovecot23 sles 15.6 | 2.3.21.1-150200.76.1 | [SUSE-SU-2026:4139-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4139-1.md) | Sep 14, 2026 |
| Linux | dovecot23 sles 15.7 | 2.3.21.1-150200.76.1 | [SUSE-SU-2026:4139-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4139-1.md) | Sep 14, 2026 |
| Linux | dovecot24 opensuse-leap 16.0 | 2.4.4-160000.2.1 | [OPENSUSE-SU-2026:21720-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21720-1.md) | Sep 1, 2026 |
| Linux | dovecot24 sles 16.0 | 2.4.4-160000.2.1 | [SUSE-SU-2026:23595-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23595-1.md) | Sep 1, 2026 |

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