CVE-2026-27852

dovecot: Dovecot is an IMAP server for Linux and other UNIX-like systems, written primarily with security in mind

CVE-2026-27852 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.

High
CVSS
9.1
Important
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0043
37th percentile

Dovecot is an IMAP server for Linux and other UNIX-like systems, written primarily with security in mind. It also contains a small POP3 server, and supports e-mail in either the maildir or mbox format. The SQL drivers and authentication plug-ins are provided as subpackages. Security Fix(es): * dovecot: Dovecot: Denial of Service via IMAP ID command with excessive parameters (CVE-2026-42391) * dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation (CVE-2026-73208) * dovecot: Dovecot: Denial of service via crafted email headers (CVE-2026-27852) * dovecot: Dovecot: Denial of Service via truncated quoted argument in ManageSieve (CVE-2026-40019) * dovecot: Dovecot: Denial of Service and potential message duplication via connection limit exhaustion (CVE-2026-33263) * dovecot: Dovecot: Denial of Service in ManageSieve login process (CVE-2026-33605) * dovecot: Dovecot: Arbitrary Code Execution via Sieve editheader use-after-free (CVE-2026-42007) * dovecot: Dovecot: MySQL multi-byte escaping wrong (CVE-2026-40018) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Where it's fixed

ProductFixed inFixReleased
Linux
dovecot · Debian 12.15 (bookworm) 1:2.3.19.1+dfsg1-2.1+deb12u7 DEBIAN-CVE-2026-27852 Sep 10, 2026
dovecot · Debian 13.5 (trixie) 1:2.4.1+dfsg1-6+deb13u7 DEBIAN-CVE-2026-27852 Sep 10, 2026
dovecot · Debian 14 1:2.4.5+dfsg1-1 DEBIAN-CVE-2026-27852 Sep 10, 2026
dovecot · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot · RHEL 10 2.3.21-19.el10_2.8 RHSA-2026:79371 Aug 28, 2026
dovecot · RHEL 8 1:2.3.16-16.el8_10 RHSA-2026:76763 Oct 6, 2026
dovecot · RHEL 9 1:2.3.16-18.el9_8.8 RHSA-2026:80825 Oct 13, 2026
dovecot · almalinux 10 1:2.3.21-19.el10_2.8 ALSA-2026:79371 Oct 8, 2026
dovecot · almalinux 8 1:2.3.16-16.el8_10 ALSA-2026:76763 Oct 6, 2026
dovecot · almalinux 9 1:2.3.16-18.el9_8.8 ALSA-2026:80825 Nov 7, 2026
dovecot · amzn 2023 1:2.3.20-1.amzn2023.0.4 ALAS2023-2026-3109 Sep 28, 2026
dovecot · ol 10 1:2.3.21-19.el10_2.8 ELSA-2026-79371 Oct 8, 2026
dovecot · ol 8 1:2.3.16-16.el8_10 ELSA-2026-76763 Oct 6, 2026
dovecot · ol 9 1:2.3.16-18.el9_8.8 ELSA-2026-80825 Nov 7, 2026
dovecot · rocky 10 1:2.3.21-19.el10_2.8 RLSA-2026:79371 Nov 7, 2026
dovecot · rocky 8 1:2.3.16-16.el8_10 RLSA-2026:76763 Oct 7, 2026
dovecot · rocky 9 1:2.3.16-18.el9_8.8 RLSA-2026:80825 Nov 7, 2026
dovecot-debuginfo · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-debuginfo · amzn 2023 1:2.3.20-1.amzn2023.0.4 ALAS2023-2026-3109 Sep 28, 2026
dovecot-debugsource · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-debugsource · amzn 2023 1:2.3.20-1.amzn2023.0.4 ALAS2023-2026-3109 Sep 28, 2026
dovecot-devel · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-devel · RHEL 8 1:2.3.16-16.el8_10 RHSA-2026:76763 Oct 6, 2026
dovecot-devel · RHEL 9 1:2.3.16-18.el9_8.8 RHSA-2026:80825 Oct 13, 2026
dovecot-devel · almalinux 10 1:2.3.21-19.el10_2.8 ALSA-2026:79371 Oct 8, 2026
dovecot-devel · almalinux 8 1:2.3.16-16.el8_10 ALSA-2026:76763 Oct 6, 2026
dovecot-devel · almalinux 9 1:2.3.16-18.el9_8.8 ALSA-2026:80825 Nov 7, 2026
dovecot-devel · amzn 2023 1:2.3.20-1.amzn2023.0.4 ALAS2023-2026-3109 Sep 28, 2026
dovecot-devel · ol 10 1:2.3.21-19.el10_2.8 ELSA-2026-79371 Oct 8, 2026
dovecot-devel · ol 8 1:2.3.16-16.el8_10 ELSA-2026-76763 Oct 6, 2026
dovecot-devel · ol 9 1:2.3.16-18.el9_8.8 ELSA-2026-80825 Nov 7, 2026
dovecot-mysql · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-mysql · RHEL 8 1:2.3.16-16.el8_10 RHSA-2026:76763 Oct 6, 2026
dovecot-mysql · RHEL 9 1:2.3.16-18.el9_8.8 RHSA-2026:80825 Oct 13, 2026
dovecot-mysql · almalinux 10 1:2.3.21-19.el10_2.8 ALSA-2026:79371 Oct 8, 2026
dovecot-mysql · almalinux 8 1:2.3.16-16.el8_10 ALSA-2026:76763 Oct 6, 2026
dovecot-mysql · almalinux 9 1:2.3.16-18.el9_8.8 ALSA-2026:80825 Nov 7, 2026
dovecot-mysql · amzn 2023 1:2.3.20-1.amzn2023.0.4 ALAS2023-2026-3109 Sep 28, 2026
dovecot-mysql · ol 10 1:2.3.21-19.el10_2.8 ELSA-2026-79371 Oct 8, 2026
dovecot-mysql · ol 8 1:2.3.16-16.el8_10 ELSA-2026-76763 Oct 6, 2026
dovecot-mysql · ol 9 1:2.3.16-18.el9_8.8 ELSA-2026-80825 Nov 7, 2026
dovecot-mysql-debuginfo · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-mysql-debuginfo · amzn 2023 1:2.3.20-1.amzn2023.0.4 ALAS2023-2026-3109 Sep 28, 2026
dovecot-pgsql · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-pgsql · RHEL 8 1:2.3.16-16.el8_10 RHSA-2026:76763 Oct 6, 2026
dovecot-pgsql · RHEL 9 1:2.3.16-18.el9_8.8 RHSA-2026:80825 Oct 13, 2026
dovecot-pgsql · almalinux 10 1:2.3.21-19.el10_2.8 ALSA-2026:79371 Oct 8, 2026
dovecot-pgsql · almalinux 8 1:2.3.16-16.el8_10 ALSA-2026:76763 Oct 6, 2026
dovecot-pgsql · almalinux 9 1:2.3.16-18.el9_8.8 ALSA-2026:80825 Nov 7, 2026
dovecot-pgsql · amzn 2023 1:2.3.20-1.amzn2023.0.4 ALAS2023-2026-3109 Sep 28, 2026
dovecot-pgsql · ol 10 1:2.3.21-19.el10_2.8 ELSA-2026-79371 Oct 8, 2026
dovecot-pgsql · ol 8 1:2.3.16-16.el8_10 ELSA-2026-76763 Oct 6, 2026
dovecot-pgsql · ol 9 1:2.3.16-18.el9_8.8 ELSA-2026-80825 Nov 7, 2026
dovecot-pgsql-debuginfo · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-pgsql-debuginfo · amzn 2023 1:2.3.20-1.amzn2023.0.4 ALAS2023-2026-3109 Sep 28, 2026
dovecot-pigeonhole · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-pigeonhole · RHEL 8 1:2.3.16-16.el8_10 RHSA-2026:76763 Oct 6, 2026
dovecot-pigeonhole · RHEL 9 1:2.3.16-18.el9_8.8 RHSA-2026:80825 Oct 13, 2026
dovecot-pigeonhole · almalinux 10 1:2.3.21-19.el10_2.8 ALSA-2026:79371 Oct 8, 2026
dovecot-pigeonhole · almalinux 8 1:2.3.16-16.el8_10 ALSA-2026:76763 Oct 6, 2026
dovecot-pigeonhole · almalinux 9 1:2.3.16-18.el9_8.8 ALSA-2026:80825 Nov 7, 2026
dovecot-pigeonhole · amzn 2023 1:2.3.20-1.amzn2023.0.4 ALAS2023-2026-3109 Sep 28, 2026
dovecot-pigeonhole · ol 10 1:2.3.21-19.el10_2.8 ELSA-2026-79371 Oct 8, 2026
dovecot-pigeonhole · ol 8 1:2.3.16-16.el8_10 ELSA-2026-76763 Oct 6, 2026
dovecot-pigeonhole · ol 9 1:2.3.16-18.el9_8.8 ELSA-2026-80825 Nov 7, 2026
dovecot-pigeonhole-debuginfo · Fedora 43 1:2.4.5-1.fc43 FEDORA-2026-E8A6485109 Sep 10, 2026
dovecot-pigeonhole-debuginfo · amzn 2023 1:2.3.20-1.amzn2023.0.4 ALAS2023-2026-3109 Sep 28, 2026
dovecot23 · sles 15.6 2.3.21.1-150200.76.1 SUSE-SU-2026:4139-1 Sep 14, 2026
dovecot23 · sles 15.7 2.3.21.1-150200.76.1 SUSE-SU-2026:4139-1 Sep 14, 2026
dovecot24 · opensuse-leap 16.0 2.4.4-160000.2.1 OPENSUSE-SU-2026:21720-1 Sep 1, 2026
dovecot24 · sles 16.0 2.4.4-160000.2.1 SUSE-SU-2026:23595-1 Sep 1, 2026

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