CVE-2026-40014

EUVD-2026-67664

28.08.2026, 12:16

An attacker that can send mail to a user can craft a message header that makes the IMAP THREAD command consume CPU disproportionate to the size of the message. When a mail client issues a THREAD command on the affected mailbox, this can cause degradation or denial of service for IMAP. Monitor system for abnormal CPU usage, kill the offending process and remove the offending message from the affected mailbox. Update to non-vulnerable version. No publicly available exploits are known.

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	6.5 MEDIUM	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Awaiting analysis

This vulnerability is currently awaiting analysis.

Base Score

CVSS 3.x

EPSS Score

Percentile: 24.9%

Debian Releases

Debian Product

Codename

dovecot

bookworm	vulnerable
bookworm (security)	vulnerable
forky	1:2.4.5+dfsg1-2 fixed
sid	1:2.4.5+dfsg1-3 fixed
trixie	vulnerable
trixie (security)	1:2.4.1+dfsg1-6+deb13u7 fixed

Ubuntu Releases

Ubuntu Product

Codename

dovecot

bionic	needs-triage
focal	needs-triage
jammy	needs-triage
noble	needs-triage
resolute	needs-triage
trusty	needs-triage
xenial	needs-triage

openSUSE / SLES Releases

openSUSE Product

Release

dovecot22

suse enterprise sap 12 SP5	2.2.31-19.40.1 fixed
suse enterprise server 12 SP3	2.2.31-19.40.1 fixed
suse enterprise server 12 SP5	2.2.31-19.40.1 fixed

dovecot22-backend-mysql

suse enterprise sap 12 SP5	2.2.31-19.40.1 fixed
suse enterprise server 12 SP3	2.2.31-19.40.1 fixed
suse enterprise server 12 SP5	2.2.31-19.40.1 fixed

dovecot22-backend-pgsql

suse enterprise sap 12 SP5	2.2.31-19.40.1 fixed
suse enterprise server 12 SP3	2.2.31-19.40.1 fixed
suse enterprise server 12 SP5	2.2.31-19.40.1 fixed

dovecot22-backend-sqlite

suse enterprise sap 12 SP5	2.2.31-19.40.1 fixed
suse enterprise server 12 SP3	2.2.31-19.40.1 fixed
suse enterprise server 12 SP5	2.2.31-19.40.1 fixed

dovecot22-devel

suse enterprise sap 12 SP5	2.2.31-19.40.1 fixed
suse enterprise server 12 SP5	2.2.31-19.40.1 fixed

dovecot23

suse enterprise sap 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP7	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP7	2.3.21.1-150200.76.1 fixed

dovecot23-backend-mysql

suse enterprise sap 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP7	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP7	2.3.21.1-150200.76.1 fixed

dovecot23-backend-pgsql

suse enterprise sap 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP7	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP7	2.3.21.1-150200.76.1 fixed

dovecot23-backend-sqlite

suse enterprise sap 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP7	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP7	2.3.21.1-150200.76.1 fixed

dovecot23-devel

suse enterprise sap 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP7	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP7	2.3.21.1-150200.76.1 fixed

dovecot23-fts

suse enterprise sap 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP7	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP7	2.3.21.1-150200.76.1 fixed

dovecot23-fts-lucene

suse enterprise sap 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP7	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP7	2.3.21.1-150200.76.1 fixed

dovecot23-fts-solr

suse enterprise sap 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP7	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP7	2.3.21.1-150200.76.1 fixed

dovecot23-fts-squat

suse enterprise sap 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise sap 15 SP7	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP4	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP5	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP6	2.3.21.1-150200.76.1 fixed
suse enterprise server 15 SP7	2.3.21.1-150200.76.1 fixed

Common Weakness Enumeration

CWE-400 - Uncontrolled Resource Consumption
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.

Vulnerability Media Exposure

[GERMAN] Dovecot: Mehrere Schwachstellen
Ein Angreifer kann mehrere Schwachstellen in Dovecot ausnutzen, um Sicherheitsvorkehrungen zu umgehen, sensible Informationen offenzulegen, Daten zu manipulieren oder Denial-of-Service-Zustände herbeizuführen.
Published: 2026-08-27T22:00:00+00:00

References

https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json