Description
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.
Published: 2026-03-27
Score: 7.4 High
EPSS: < 1% Very Low
KEV: No
Impact: Credential disclosure leading to full control
Action: Immediate Patch
AI Analysis

Impact

The vulnerability stems from Doveadm's use of direct string comparison for credential verification, creating a timing side‑channel that allows an attacker to infer the correct credentials. Discovery of the correct credentials enables an attacker to gain full access to the affected Dovecot service, providing both confidentiality and integrity compromise. This weakness is referenced as CWE‑208 and CWE‑287.

Affected Systems

The affected product is OX Dovecot Pro from Open‑Xchange GmbH. No specific version information is supplied, so all installations should verify whether the vendor’s patch applies to their environment.

Risk and Exploitability

The CVSS base score of 7.4 indicates a high severity, while the EPSS score of less than 1% suggests a low probability of exploitation at present. The vulnerability is not listed in CISA’s KEV catalog. Attacks would most likely exploit the doveadm HTTP service over the network; the description implies the attacker requires only access to the HTTP port. No publicly available exploits are known, but the potential for a timely exploitation exists once the port is reachable.

Generated by OpenCVE AI on March 30, 2026 at 13:21 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Install the vendor‑supplied fixed version of OX Dovecot Pro
  • Restrict network access to the doveadm HTTP service port to trusted hosts only

Generated by OpenCVE AI on March 30, 2026 at 13:21 UTC.

Tracking

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Advisories
Source ID Title
Debian DSA Debian DSA DSA-6197-1 dovecot security update
Ubuntu USN Ubuntu USN USN-8136-1 Dovecot vulnerabilities
History

Wed, 29 Apr 2026 19:30:00 +0000

Type Values Removed Values Added
First Time appeared Dovecot
Dovecot dovecot
Open-xchange dovecot
Weaknesses NVD-CWE-Other
CPEs cpe:2.3:a:dovecot:dovecot:*:*:*:*:*:*:*:*
cpe:2.3:a:open-xchange:dovecot:*:*:*:*:pro:*:*:*
Vendors & Products Dovecot
Dovecot dovecot
Open-xchange dovecot

Mon, 30 Mar 2026 12:15:00 +0000

Type Values Removed Values Added
Title Timing Oracle Allows Credential Harvesting in OX Dovecot Pro dovecot: Doveadm: Full access via timing oracle attack in credential verification
Weaknesses CWE-208
References
Metrics threat_severity

None

threat_severity

Important


Mon, 30 Mar 2026 07:15:00 +0000

Type Values Removed Values Added
First Time appeared Open-xchange
Open-xchange ox Dovecot Pro
Vendors & Products Open-xchange
Open-xchange ox Dovecot Pro

Fri, 27 Mar 2026 20:30:00 +0000

Type Values Removed Values Added
Title Timing Oracle Allows Credential Harvesting in OX Dovecot Pro

Fri, 27 Mar 2026 14:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Fri, 27 Mar 2026 08:30:00 +0000

Type Values Removed Values Added
Description 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.
Weaknesses CWE-287
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'}


Subscriptions

Dovecot Dovecot
Open-xchange Dovecot Ox Dovecot Pro
cve-icon MITRE

Status: PUBLISHED

Assigner: OX

Published:

Updated: 2026-03-27T13:45:12.231Z

Reserved: 2026-02-24T08:46:09.373Z

Link: CVE-2026-27856

cve-icon Vulnrichment

Updated: 2026-03-27T13:21:53.180Z

cve-icon NVD

Status : Analyzed

Published: 2026-03-27T09:16:19.767

Modified: 2026-04-29T19:25:51.433

Link: CVE-2026-27856

cve-icon Redhat

Severity : Important

Publid Date: 2026-03-27T08:10:19Z

Links: CVE-2026-27856 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-03-30T20:57:05Z