{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-27858", "assignerOrgId": "8ce71d90-2354-404b-a86e-bec2cc4e6981", "state": "PUBLISHED", "assignerShortName": "OX", "dateReserved": "2026-02-24T08:46:09.374Z", "datePublished": "2026-03-27T08:10:21.424Z", "dateUpdated": "2026-07-15T01:12:45.177Z" }, "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" }, { "lessThanOrEqual": "3.1.0", "status": "affected", "version": "0", "versionType": "semver" }, { "lessThanOrEqual": "2.4.0", "status": "affected", "version": "0", "versionType": "semver" } ] } ], "descriptions": [ { "lang": "en", "value": "Attacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount of memory.\r\n Attacker can force managesieve-login to be unavailable by repeatedly crashing the process. Protect access to managesieve protocol, or install fixed version. No publicly available exploits are known." } ], "metrics": [ { "cvssV3_1": { "attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1" }, "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ] } ], "problemTypes": [ { "descriptions": [ { "cweId": "CWE-400", "description": "Uncontrolled Resource Consumption", "lang": "en", "type": "cwe" } ] } ], "providerMetadata": { "orgId": "8ce71d90-2354-404b-a86e-bec2cc4e6981", "shortName": "OX", "dateUpdated": "2026-03-27T12:33:31.126Z" }, "references": [ { "tags": [ "vendor-advisory" ], "url": "https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json" } ], "source": { "defect": "DOV-8818", "discovery": "EXTERNAL" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-03-27T12:36:26.526829Z", "id": "CVE-2026-27858", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-03-27T12:37:09.762Z" } }, { "affected": [ { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:10.1", "cpe:/o:redhat:enterprise_linux:10.2" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 10", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.21-16.el10_1.1", "versionType": "rpm" }, { "lessThan": "*", "status": "unaffected", "version": "1:2.3.21-19.el10_2", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux_eus:10.0" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 10.0 Extended Update Support", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.21-16.el10_0.1", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:rhel_els:7" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 7 Extended Lifecycle Support", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.2.36-8.el7_9.1", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:enterprise_linux:8" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 8", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-7.el8_10", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_aus:8.4" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.8-9.el8_4.1", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_eus_long_life:8.4" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.8-9.el8_4.1", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_aus:8.6" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-2.el8_6.1", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_tus:8.6" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 8.6 Telecommunications Update Service", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-2.el8_6.1", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_e4s:8.6" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-2.el8_6.1", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_tus:8.8" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 8.8 Telecommunications Update Service", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-3.el8_8.1", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_e4s:8.8" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-3.el8_8.1", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:enterprise_linux:9" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 9", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-15.el9_7.1", "versionType": "rpm" }, { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-18.el9_8", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_e4s:9.0" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-3.el9_0.1", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_e4s:9.2" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-8.el9_2.2", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_eus:9.4" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 9.4 Extended Update Support", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-11.el9_4.2", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_eus:9.6" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 9.6 Extended Update Support", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-15.el9_6.1", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:6" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 6", "vendor": "Red Hat" } ], "datePublic": "2026-03-27T08:10:21.424Z", "descriptions": [ { "lang": "en", "value": "A flaw was found in dovecot. An unauthenticated and remote attacker can send a crafted message that causes managesieve to allocate an excessive amount of memory, forcing managesieve-login to be unavailable by repeatedly crashing the process, resulting in a denial of service." } ], "metrics": [ { "other": { "content": { "namespace": "https://access.redhat.com/security/updates/classification/", "value": "Important" }, "type": "Red Hat severity rating" } }, { "cvssV3_1": { "attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1" }, "format": "CVSS" } ], "problemTypes": [ { "descriptions": [ { "cweId": "CWE-770", "description": "Allocation of Resources Without Limits or Throttling", "lang": "en", "type": "CWE" } ] } ], "references": [ { "tags": [ "vdb-entry", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/security/cve/CVE-2026-27858" }, { "name": "RHBZ#2452175", "tags": [ "issue-tracking", "x_refsource_REDHAT" ], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2452175" }, { "tags": [ "x_sadp-csaf-vex" ], "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27858.json" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:26564" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:17602" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:13498" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:19149" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:13830" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:19455" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:19453" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:18053" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:17630" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:17628" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:17625" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:17626" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:13857" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:19364" } ], "solutions": [ { "lang": "en", "value": "RHSA-2026:26564: Red Hat Enterprise Linux Server (v. 7 ELS), Red Hat Enterprise Linux Server Optional (v. 7 ELS)" }, { "lang": "en", "value": "RHSA-2026:17602: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)" }, { "lang": "en", "value": "RHSA-2026:13498: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)" }, { "lang": "en", "value": "RHSA-2026:19149: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)" }, { "lang": "en", "value": "RHSA-2026:13830: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux CRB (v. 8)" }, { "lang": "en", "value": "RHSA-2026:19455: Red Hat Enterprise Linux AppStream AUS (v.8.4), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4)" }, { "lang": "en", "value": "RHSA-2026:19453: Red Hat Enterprise Linux AppStream AUS (v.8.6), Red Hat Enterprise Linux AppStream E4S (v.8.6), Red Hat Enterprise Linux AppStream TUS (v.8.6)" }, { "lang": "en", "value": "RHSA-2026:18053: Red Hat Enterprise Linux AppStream E4S (v.8.8), Red Hat Enterprise Linux AppStream TUS (v.8.8)" }, { "lang": "en", "value": "RHSA-2026:17630: Red Hat Enterprise Linux AppStream E4S (v.9.0)" }, { "lang": "en", "value": "RHSA-2026:17628: Red Hat Enterprise Linux AppStream E4S (v.9.2)" }, { "lang": "en", "value": "RHSA-2026:17625: Red Hat CodeReady Linux Builder EUS (v.9.4), Red Hat Enterprise Linux AppStream EUS (v.9.4)" }, { "lang": "en", "value": "RHSA-2026:17626: Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux AppStream EUS (v.9.6)" }, { "lang": "en", "value": "RHSA-2026:13857: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)" }, { "lang": "en", "value": "RHSA-2026:19364: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)" } ], "timeline": [ { "lang": "en", "time": "2026-03-27T09:01:45.192Z", "value": "Reported to Red Hat." }, { "lang": "en", "time": "2026-03-27T08:10:21.424Z", "value": "Made public." } ], "title": "dovecot: denial of service via crafted message before authentication", "workarounds": [ { "lang": "en", "value": "To mitigate this vulnerability, protect access to the managesieve protocol by configuring firewall rules to restrict access to the managesieve port and only allow connections from trusted IP addresses or networks." } ], "x_adpType": "supplier", "x_generator": { "engine": "sadp-cli 1.0.0" }, "providerMetadata": { "orgId": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "shortName": "redhat-SADP", "dateUpdated": "2026-07-15T01:12:45.177Z" } } ] } }