{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-42006", "assignerOrgId": "8ce71d90-2354-404b-a86e-bec2cc4e6981", "state": "PUBLISHED", "assignerShortName": "OX", "dateReserved": "2026-04-23T11:15:21.199Z", "datePublished": "2026-05-12T13:28:46.922Z", "dateUpdated": "2026-08-03T12:05:50.626Z" }, "containers": { "cna": { "affected": [ { "defaultStatus": "unaffected", "modules": [ "core" ], "product": "OX Dovecot Pro", "vendor": "Open-Xchange GmbH", "versions": [ { "lessThanOrEqual": "3.0.5", "status": "affected", "version": "0", "versionType": "semver" }, { "lessThanOrEqual": "3.1.4", "status": "affected", "version": "0", "versionType": "semver" }, { "lessThanOrEqual": "2.4.3", "status": "affected", "version": "0", "versionType": "semver" } ] } ], "descriptions": [ { "lang": "en", "value": "An attacker can cause uncontrolled memory usage with excessive bracing over IMAP. The fix in CVE-2026-27857 was incomplete, only blocking one way of doing this, so there was still another way left open. In particular, the fix was for closing braces, but you could still use open braces to bypass the limit. Using excessive bracing, attacker can cause memory usage up to configured memory limit. Install fixed version, or configure vsz_limit for imap process to low value. No publicly available exploits are known." } ], "metrics": [ { "cvssV3_1": { "attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 4.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L", "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": "2026-05-12T13:39:06.099Z" }, "references": [ { "tags": [ "vendor-advisory" ], "url": "https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json" } ], "source": { "defect": "DOV-9138", "discovery": "EXTERNAL" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-05-12T15:40:29.845540Z", "id": "CVE-2026-42006", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "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": "2026-05-12T15:40:38.913Z" } }, { "affected": [ { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "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": "1:2.3.21-19.el10_2.1", "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_0.2", "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_9.2", "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": "1:2.3.16-8.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_4.2", "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_4.2", "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_6.2", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_eus_long_life:8.6" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-2.el8_6.2", "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_8.2", "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_8.2", "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": "1:2.3.16-18.el9_8.1", "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_2.3", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:rhel_e4s:9.4" ], "defaultStatus": "affected", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions", "vendor": "Red Hat", "versions": [ { "lessThan": "*", "status": "unaffected", "version": "1:2.3.16-11.el9_4.3", "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_6.2", "versionType": "rpm" } ] }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:6" ], "defaultStatus": "unknown", "packageName": "dovecot", "product": "Red Hat Enterprise Linux 6", "vendor": "Red Hat" } ], "datePublic": "2026-05-12T13:28:46.922Z", "descriptions": [ { "lang": "en", "value": "A flaw was found in Dovecot. A remote attacker can exploit this vulnerability by sending excessive open braces over the Internet Message Access Protocol (IMAP), leading to uncontrolled memory usage. This can cause the affected system to consume memory up to its configured limit, resulting in a Denial of Service (DoS)." } ], "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-2026-42006" }, { "name": "RHBZ#2476476", "tags": [ "issue-tracking", "x_refsource_REDHAT" ], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2476476" }, { "tags": [ "x_sadp-csaf-vex" ], "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42006.json" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:49513" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:42091" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:41988" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:46532" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:46380" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:46379" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:46381" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:44373" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:44357" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:44355" }, { "tags": [ "vendor-advisory", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/errata/RHSA-2026:41905" } ], "solutions": [ { "lang": "en", "value": "RHSA-2026:49513: Red Hat Enterprise Linux Server (v. 7 ELS)" }, { "lang": "en", "value": "RHSA-2026:42091: Red Hat Enterprise Linux AppStream EUS (v. 10.0)" }, { "lang": "en", "value": "RHSA-2026:41988: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)" }, { "lang": "en", "value": "RHSA-2026:46532: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux CRB (v. 8)" }, { "lang": "en", "value": "RHSA-2026:46380: Red Hat Enterprise Linux AppStream AUS (v.8.4), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4)" }, { "lang": "en", "value": "RHSA-2026:46379: Red Hat Enterprise Linux AppStream AUS (v.8.6), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)" }, { "lang": "en", "value": "RHSA-2026:46381: Red Hat Enterprise Linux AppStream E4S (v.8.8), Red Hat Enterprise Linux AppStream TUS (v.8.8)" }, { "lang": "en", "value": "RHSA-2026:44373: Red Hat Enterprise Linux AppStream E4S (v.9.2)" }, { "lang": "en", "value": "RHSA-2026:44357: Red Hat Enterprise Linux AppStream E4S (v.9.4)" }, { "lang": "en", "value": "RHSA-2026:44355: Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux AppStream EUS (v.9.6)" }, { "lang": "en", "value": "RHSA-2026:41905: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)" } ], "timeline": [ { "lang": "en", "time": "2026-05-12T14:02:01.841Z", "value": "Reported to Red Hat." }, { "lang": "en", "time": "2026-05-12T13:28:46.922Z", "value": "Made public." } ], "title": "dovecot: Dovecot: Denial of Service via excessive IMAP bracing", "workarounds": [ { "lang": "en", "value": "To mitigate this issue, administrators can configure the `vsz_limit` setting for the Dovecot IMAP process to a lower value. This limits the virtual memory size available to the IMAP process, preventing excessive memory consumption.\n\nExample configuration in `/etc/dovecot/conf.d/10-master.conf`:\n```\nservice imap {\n vsz_limit = 256M\n}\n```\nAfter modifying the configuration, restart the Dovecot service for the changes to take effect.\n```bash\nsystemctl restart dovecot\n```\nSetting `vsz_limit` too low may impact legitimate IMAP operations. \n\n*Restarting the dovecot service will temporarily interrupt mail services." } ], "x_adpType": "supplier", "x_generator": { "engine": "sadp-cli 1.0.0" }, "providerMetadata": { "orgId": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "shortName": "redhat-SADP", "dateUpdated": "2026-08-03T12:05:50.626Z" } } ] } }