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

26 Oct 2026, 21:10

Type	Values Removed	Values Added
Summary		(es) Las credenciales de Doveadm se verifican mediante comparación directa, lo cual es susceptible a un ataque de oráculo de tiempo. Un atacante puede usar esto para determinar las credenciales configuradas. Averiguar la credencial conducirá a un acceso total al componente afectado. Limite el acceso al puerto del servicio HTTP de doveadm, instale la versión corregida. No se conocen exploits disponibles públicamente.

Information

Published : 2026-03-27 09:16

Updated : 2026-10-26 21:10

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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