CVE-2026-27856

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.

CVSS v3 7.4 HIGH

7.4^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.2 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

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-2026:26564
https://access.redhat.com/security/cve/CVE-2026-27856
https://bugzilla.redhat.com/show_bug.cgi?id=2452171
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27856.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-2026-27856

Mitre link : CVE-2026-27856

CVE.ORG link : CVE-2026-27856

JSON object : View

Products Affected

open-xchange

dovecot

dovecot

dovecot

CWE

CWE-287

Improper Authentication

NVD-CWE-Other CWE-208

Observable Timing Discrepancy

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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."}], "lastModified": "2026-07-15T02:19:10.880", "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"}