CVE-2026-40016
MEDIUM EPSS 25.6%
Published May 12, 20261mo ago · Modified Jun 17, 20262w ago
6.5 CVSS 3.1
Published May 12, 2026 1mo ago
Last Modified Jun 17, 2026 2w ago
Description
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 Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High
Threat Intelligence
EPSS Exploit Probability
25.6% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available
Weaknesses 1
CWE-400 Uncontrolled Resource Consumption Resource Mgmt
Affected Products 2
| Vendor | Product | Version | Range |
|---|---|---|---|
| dovecot | dovecot | * | <2.4.4 |
| open-xchange | dovecot | * | <3.1.5 |
References 1
- documentation.open-xchange.com https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.