CVE-2026-52681

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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": "2.3.15", "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": "2.3.15", "versionType": "semver"}]}], "source": "security@open-xchange.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Sieve CPU resource usage is tracked in the compiled script, so an attacker that has valid credentials can reset the accounting by repeatedly changing the active script. Compiled script files are also not removed when a script is deleted or renamed. The configured Sieve CPU limit can be bypassed, allowing sustained CPU consumption, and the leftover files increase disk consumption. Both can cause degradation of service for mail delivery. Monitor system for abnormal CPU usage and disk consumption. Update to non-vulnerable version. No publicly available exploits are known."}], "id": "CVE-2026-52681", "lastModified": "2026-09-03T18:13:44.643", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 3.1, "baseSeverity": "LOW", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L", "version": "3.1"}, "exploitabilityScore": 1.6, "impactScore": 1.4, "source": "security@open-xchange.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-52681", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-08-28T14:32:25.916844Z", "version": "2.0.3"}}]}, "published": "2026-08-28T12:16:30.010", "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-1050"}], "source": "security@open-xchange.com", "type": "Secondary"}]}

{"bugzilla": {"description": "dovecot: Dovecot: Denial of Service via Sieve script manipulation", "id": "2525582", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2525582"}, "csaw": false, "cvss3": {"cvss3_base_score": "3.1", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L", "status": "draft"}, "cwe": "CWE-770", "details": ["Sieve CPU resource usage is tracked in the compiled script, so an attacker that has valid credentials can reset the accounting by repeatedly changing the active script. Compiled script files are also not removed when a script is deleted or renamed. The configured Sieve CPU limit can be bypassed, allowing sustained CPU consumption, and the leftover files increase disk consumption. Both can cause degradation of service for mail delivery. Monitor system for abnormal CPU usage and disk consumption. Update to non-vulnerable version. No publicly available exploits are known.", "A flaw was found in dovecot. An authenticated attacker can bypass the configured Sieve CPU limit by repeatedly changing active scripts. This action prevents proper CPU resource accounting and leaves behind compiled script files, leading to sustained CPU and increased disk consumption. The consequence is a degradation of service for mail delivery, potentially causing a Denial of Service (DoS)."], "mitigation": {"lang": "en:us", "value": "Administrators can monitor system resources for abnormal CPU usage and disk consumption related to Dovecot Sieve processes. To prevent exploitation, if Sieve functionality is not required, it can be disabled by removing the `sieve` plugin from the `mail_plugins` setting in the Dovecot configuration. Disabling Sieve will impact user mail filtering capabilities. A restart of the Dovecot service is required for configuration changes to take effect."}, "name": "CVE-2026-52681", "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": "Not affected", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "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": "2026-08-28T10:12:30Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-52681\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-52681\nhttps://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json"], "threat_severity": "Low"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2.3.15,2.4.5)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "manual", "scores": [{"score": 100.0, "source": "manual"}]}, "original": {"product": "OX Dovecot CE", "source": "cna", "vendor": "Open-Xchange GmbH"}, "product": "ox_dovecot_ce", "vendor": "open-xchange"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[2.3.15,2.3.22.2)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.0.0,3.0.7)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.1.0,3.1.6)"}}], "enrichment": {"confidence": 92.0, "confidence_source": "matching", "scores": [{"score": 92.0, "source": "matching"}]}, "original": {"product": "OX Dovecot Pro", "source": "cna", "vendor": "Open-Xchange GmbH"}, "product": "ox_dovecot_pro", "vendor": "open-xchange"}], "created": "2026-08-28T13:45:17.301556+00:00", "updated": "2026-09-01T15:00:11.903310+00:00", "vendors": ["open-xchange", "open-xchange$PRODUCT$ox_dovecot_ce", "open-xchange$PRODUCT$ox_dovecot_pro"]}