{"id":"CVE-2026-40016","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-40016","generatedAt":"2026-10-28T02:13:46.478Z","title":"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.","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.","published":"2026-05-12T14:17:04.000Z","lastModified":"2026-10-26T18:10:00.000Z","status":"Analyzed","sourceIdentifier":"security@open-xchange.com","cvss":{"version":"3.1","score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-400"],"affected":["dovecot/dovecot","open-xchange/dovecot"],"epss":{"score":0.00338,"percentile":0.26973,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.34%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json","tags":["Vendor Advisory"],"source":"security@open-xchange.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-40016","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}