CVE-2026-27858

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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json	Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:13498
https://access.redhat.com/errata/RHSA-2026:13830
https://access.redhat.com/errata/RHSA-2026:13857
https://access.redhat.com/errata/RHSA-2026:17602
https://access.redhat.com/errata/RHSA-2026:17625
https://access.redhat.com/errata/RHSA-2026:17626
https://access.redhat.com/errata/RHSA-2026:17628
https://access.redhat.com/errata/RHSA-2026:17630
https://access.redhat.com/errata/RHSA-2026:18053
https://access.redhat.com/errata/RHSA-2026:19149
https://access.redhat.com/errata/RHSA-2026:19364
https://access.redhat.com/errata/RHSA-2026:19453
https://access.redhat.com/errata/RHSA-2026:19455
https://access.redhat.com/errata/RHSA-2026:26564
https://access.redhat.com/security/cve/CVE-2026-27858
https://bugzilla.redhat.com/show_bug.cgi?id=2452175
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27858.json

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:dovecot:dovecot::::::::
	cpe:2.3:a:open-xchange:dovecot:::::pro:::*
	cpe:2.3:a:open-xchange:dovecot:::::pro:::*
	cpe:2.3:a:open-xchange:dovecot:::::pro:::*

History

No history.

Information

Published : 2026-03-27 09:16

Updated : 2026-07-15 02:19

NVD link : CVE-2026-27858

Mitre link : CVE-2026-27858

CVE.ORG link : CVE-2026-27858

JSON object : View

Products Affected

open-xchange

dovecot

dovecot

dovecot

CWE

CWE-400

Uncontrolled Resource Consumption

CWE-770

Allocation of Resources Without Limits or Throttling

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[{"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."}], "lastModified": "2026-07-15T02:19:11.340", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:dovecot:dovecot:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "BE209329-C5EA-4EE7-A23E-CD2EC061A9A4", "versionEndExcluding": "2.4.3"}, {"criteria": "cpe:2.3:a:open-xchange:dovecot:*:*:*:*:pro:*:*:*", "vulnerable": true, "matchCriteriaId": "5CF82590-D98A-4E06-AC8C-6CC3506ED923", "versionEndExcluding": "2.3.22.1"}, {"criteria": "cpe:2.3:a:open-xchange:dovecot:*:*:*:*:pro:*:*:*", "vulnerable": true, "matchCriteriaId": "8476287B-40B2-4533-A3AB-B880516C0B5C", "versionEndExcluding": "3.0.5", "versionStartIncluding": "3.0.0"}, {"criteria": "cpe:2.3:a:open-xchange:dovecot:*:*:*:*:pro:*:*:*", "vulnerable": true, "matchCriteriaId": "11CA35AA-72CB-4614-A064-8A90F65D8A71", "versionEndExcluding": "3.1.4", "versionStartIncluding": "3.1.0"}], "operator": "OR"}]}], "sourceIdentifier": "security@open-xchange.com"}