CVE-2026-40014

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "modules": ["core"], "product": "OX Dovecot Pro", "vendor": "Open-Xchange GmbH", "versions": [{"lessThan": "2.3.22.2", "status": "affected", "version": "2.3.0", "versionType": "semver"}, {"lessThan": "3.0.7", "status": "affected", "version": "3.0.0", "versionType": "semver"}, {"lessThan": "3.1.6", "status": "affected", "version": "3.1.0", "versionType": "semver"}]}, {"defaultStatus": "unaffected", "modules": ["core"], "product": "OX Dovecot CE", "vendor": "Open-Xchange GmbH", "versions": [{"lessThan": "2.4.5", "status": "affected", "version": "2.3.0", "versionType": "semver"}]}], "source": "security@open-xchange.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2026-40014", "lastModified": "2026-09-03T18:13:44.643", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 3.6, "source": "security@open-xchange.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-40014", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-08-28T14:32:39.280100Z", "version": "2.0.3"}}]}, "published": "2026-08-28T12:16:28.240", "references": [{"source": "security@open-xchange.com", "url": "https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json"}], "sourceIdentifier": "security@open-xchange.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-400"}], "source": "security@open-xchange.com", "type": "Secondary"}]}

{"bugzilla": {"description": "dovecot: Dovecot: Denial of Service via crafted IMAP THREAD command", "id": "2525543", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2525543"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-606", "details": ["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.", "A flaw was found in Dovecot. A remote attacker, by sending a specially crafted email message header to a user, can cause the Internet Message Access Protocol (IMAP) THREAD command to consume excessive CPU resources. When a mail client processes this message, it can lead to degradation or a denial of service for the IMAP server."], "mitigation": {"lang": "en:us", "value": "To mitigate this issue, administrators should monitor Dovecot processes for abnormal CPU usage. If high CPU consumption is observed, identify and terminate the offending Dovecot process. Subsequently, remove the malicious email from the affected mailbox to prevent re-triggering the vulnerability. Restarting the Dovecot service may be required after process termination, which could temporarily impact mail service availability."}, "name": "CVE-2026-40014", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-28T10:12:17Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-40014\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-40014\nhttps://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json"], "threat_severity": "Moderate"}

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