{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-27856", "assignerOrgId": "8ce71d90-2354-404b-a86e-bec2cc4e6981", "state": "PUBLISHED", "assignerShortName": "OX", "dateReserved": "2026-02-24T08:46:09.373Z", "datePublished": "2026-03-27T08:10:19.537Z", "dateUpdated": "2026-03-27T13:45:12.231Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "modules": ["core"], "product": "OX Dovecot Pro", "vendor": "Open-Xchange GmbH", "versions": [{"lessThanOrEqual": "2.3.0", "status": "affected", "version": "0", "versionType": "semver"}]}], "descriptions": [{"lang": "en", "value": "Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack. An attacker can use this to determine the configured credentials. Figuring out the credential will lead into full access to the affected component. Limit access to the doveadm http service port, install fixed version. No publicly available exploits are known."}], "metrics": [{"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-287", "description": "Improper Authentication", "lang": "en", "type": "cwe"}]}], "providerMetadata": {"orgId": "8ce71d90-2354-404b-a86e-bec2cc4e6981", "shortName": "OX", "dateUpdated": "2026-03-27T12:33:28.219Z"}, "references": [{"tags": ["vendor-advisory"], "url": "https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json"}], "source": {"defect": "DOV-8830", "discovery": "EXTERNAL"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-03-27T13:21:44.110751Z", "id": "CVE-2026-27856", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-03-27T13:45:12.231Z"}}]}}

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{"cveTags": [], "descriptions": [{"lang": "en", "value": "Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack. An attacker can use this to determine the configured credentials. Figuring out the credential will lead into full access to the affected component. Limit access to the doveadm http service port, install fixed version. No publicly available exploits are known."}], "id": "CVE-2026-27856", "lastModified": "2026-03-30T13:26:29.793", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 5.2, "source": "security@open-xchange.com", "type": "Secondary"}]}, "published": "2026-03-27T09:16:19.767", "references": [{"source": "security@open-xchange.com", "url": "https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json"}], "sourceIdentifier": "security@open-xchange.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-287"}], "source": "security@open-xchange.com", "type": "Secondary"}]}

{"bugzilla": {"description": "dovecot: Doveadm: Full access via timing oracle attack in credential verification", "id": "2452171", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2452171"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.4", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "status": "draft"}, "cwe": "CWE-208", "details": ["A flaw was found in Doveadm, a component of Dovecot. An attacker can exploit a timing oracle vulnerability during the direct comparison of credentials. This allows the attacker to determine the configured credentials, potentially leading to full unauthorized access to the affected component."], "name": "CVE-2026-27856", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Affected", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Affected", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-03-27T08:10:19Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-27856\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-27856\nhttps://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json"], "threat_severity": "Important"}