FKIE_CVE-2026-27858
Vulnerability from fkie_nvd - Published: 2026-03-27 09:16 - Updated: 2026-06-30 03:17
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
Attacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount of memory.
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.
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| dovecot | dovecot | * | |
| open-xchange | dovecot | * | |
| open-xchange | dovecot | * | |
| open-xchange | dovecot | * |
{
"affected": [
{
"affectedData": [
{
"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"
}
]
}
],
"source": "security@open-xchange.com"
},
{
"affectedData": [
{
"cpes": [
"cpe:/o:redhat:rhel_els:7"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux Server (v. 7 ELS)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/o:redhat:rhel_els:7"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux Server Optional (v. 7 ELS)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/o:redhat:enterprise_linux_eus:10.0"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream EUS (v. 10.0)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/o:redhat:enterprise_linux:10.1",
"cpe:/o:redhat:enterprise_linux:10.2"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream (v. 10)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:enterprise_linux:8::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream (v. 8)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_aus:8.4::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream AUS (v.8.4)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_eus_long_life:8.4::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_aus:8.6::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream AUS (v.8.6)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_e4s:8.6::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream E4S (v.8.6)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_tus:8.6::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream TUS (v.8.6)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_e4s:8.8::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream E4S (v.8.8)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_tus:8.8::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream TUS (v.8.8)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_e4s:9.0::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream E4S (v.9.0)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_e4s:9.2::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream E4S (v.9.2)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_eus:9.4::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream EUS (v.9.4)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_eus:9.6::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream EUS (v.9.6)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:enterprise_linux:9::appstream"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux AppStream (v. 9)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/o:redhat:enterprise_linux_eus:10.0"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/o:redhat:enterprise_linux:10.1",
"cpe:/o:redhat:enterprise_linux:10.2"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:enterprise_linux:8::crb"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux CRB (v. 8)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_eus:9.4::crb"
],
"defaultStatus": "affected",
"product": "Red Hat CodeReady Linux Builder EUS (v.9.4)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:rhel_eus:9.6::crb"
],
"defaultStatus": "affected",
"product": "Red Hat CodeReady Linux Builder EUS (v.9.6)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/a:redhat:enterprise_linux:9::crb"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)",
"vendor": "Red Hat"
},
{
"cpes": [
"cpe:/o:redhat:enterprise_linux:6"
],
"defaultStatus": "affected",
"product": "Red Hat Enterprise Linux 6",
"vendor": "Red Hat"
}
],
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:dovecot:dovecot:*:*:*:*:*:*:*:*",
"matchCriteriaId": "BE209329-C5EA-4EE7-A23E-CD2EC061A9A4",
"versionEndExcluding": "2.4.3",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:open-xchange:dovecot:*:*:*:*:pro:*:*:*",
"matchCriteriaId": "5CF82590-D98A-4E06-AC8C-6CC3506ED923",
"versionEndExcluding": "2.3.22.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:open-xchange:dovecot:*:*:*:*:pro:*:*:*",
"matchCriteriaId": "8476287B-40B2-4533-A3AB-B880516C0B5C",
"versionEndExcluding": "3.0.5",
"versionStartIncluding": "3.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:open-xchange:dovecot:*:*:*:*:pro:*:*:*",
"matchCriteriaId": "11CA35AA-72CB-4614-A064-8A90F65D8A71",
"versionEndExcluding": "3.1.4",
"versionStartIncluding": "3.1.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"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."
}
],
"id": "CVE-2026-27858",
"lastModified": "2026-06-30T03:17:58.790",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"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"
},
"exploitabilityScore": 3.9,
"impactScore": 3.6,
"source": "security@open-xchange.com",
"type": "Secondary"
},
{
"cvssData": {
"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"
},
"exploitabilityScore": 3.9,
"impactScore": 3.6,
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-27858",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-03-27T12:36:26.526829Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-03-27T09:16:20.073",
"references": [
{
"source": "security@open-xchange.com",
"tags": [
"Vendor Advisory"
],
"url": "https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:13498"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:13830"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:13857"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:17602"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:17625"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:17626"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:17628"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:17630"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:18053"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:19149"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:19364"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:19453"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:19455"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/errata/RHSA-2026:26564"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://access.redhat.com/security/cve/CVE-2026-27858"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2452175"
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27858.json"
}
],
"sourceIdentifier": "security@open-xchange.com",
"vulnStatus": "Modified",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-400"
}
],
"source": "security@open-xchange.com",
"type": "Secondary"
},
{
"description": [
{
"lang": "en",
"value": "CWE-770"
}
],
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"type": "Secondary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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