CVE-2026-40016

Attacker can upload a malicious Sieve script over ManageSieve service (or locally) to bypass configured CPU time limits for Sieve up to 130 times of the configured limit. Attacker can use this to degrade server performance and bypass configured CPU time limits for Sieve scripts. Install fixed version, or alternatively prevent direct access to Sieve scripts via ManageSieve or local access. No publicly available exploits are known.

CVSS v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.6 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:dovecot:dovecot::::::::
	cpe:2.3:a:open-xchange:dovecot:::::pro:::*

History

18 May 2026, 17:34

Type	Values Removed	Values Added
References	~~() https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json -~~	() https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json - Vendor Advisory
First Time		Dovecot Dovecot dovecot Open-xchange Open-xchange dovecot
CPE		cpe:2.3:a:dovecot:dovecot:::::::: cpe:2.3:a:open-xchange:dovecot:::::pro:::*

12 May 2026, 14:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-05-12 14:17

Updated : 2026-05-18 17:34

NVD link : CVE-2026-40016

Mitre link : CVE-2026-40016

CVE.ORG link : CVE-2026-40016

JSON object : View

Products Affected

dovecot

dovecot

open-xchange

dovecot

CWE

CWE-400

Uncontrolled Resource Consumption

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