Description
Attacker can use a specially crafted base64 exchange between Dovecot and Client to fake SCRAM TLS channel binding. This requires that the attacker is able to position itself between Dovecot and the client connection. If successful, the attacker can eavesdrop communications between Dovecot and client as MITM proxy. Install fixed version. No publicly available exploits are known.
Published: 2026-05-12
Score: 6.8 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Tue, 12 May 2026 15:45:00 +0000

Type Values Removed Values Added
Title Fake SCRAM TLS Channel Binding Allows MITM Eavesdropping in OX Dovecot Pro
First Time appeared Open-xchange
Open-xchange ox Dovecot Pro
Vendors & Products Open-xchange
Open-xchange ox Dovecot Pro

Tue, 12 May 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Tue, 12 May 2026 14:00:00 +0000

Type Values Removed Values Added
Description Attacker can use a specially crafted base64 exchange between Dovecot and Client to fake SCRAM TLS channel binding. This requires that the attacker is able to position itself between Dovecot and the client connection. If successful, the attacker can eavesdrop communications between Dovecot and client as MITM proxy. Install fixed version. No publicly available exploits are known.
Weaknesses CWE-99
References
Metrics cvssV3_1

{'score': 6.8, 'vector': 'CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'}


Subscriptions

Open-xchange Ox Dovecot Pro
cve-icon MITRE

Status: PUBLISHED

Assigner: OX

Published:

Updated: 2026-05-12T15:08:00.334Z

Reserved: 2026-03-23T12:58:38.266Z

Link: CVE-2026-33603

cve-icon Vulnrichment

Updated: 2026-05-12T15:07:55.507Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-12T14:17:01.600

Modified: 2026-05-12T15:08:22.857

Link: CVE-2026-33603

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-12T15:30:18Z

Weaknesses