CVE-2026-40016
5.3 · MEDIUMOverview
CVE-2026-40016 is a medium-severity vulnerability affecting dovecot dovecot. It was published on May 12, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical 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.
Remediation
Check the references section for vendor advisories and patches from dovecot. Update dovecot to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| dovecot | dovecot | >= 0, < 2.4.4 | Affected |
| open-xchange | dovecot | >= 0, < 3.1.5 | Affected |
Frequently Asked Questions
What is CVE-2026-40016?
CVE-2026-40016 is a medium-severity vulnerability affecting dovecot dovecot. It was published on May 12, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
How severe is CVE-2026-40016?
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-40016?
Check the references section for vendor advisories and patches from dovecot. Update dovecot to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-40016?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-40016 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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