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CVE-2026-33603 Details

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.

Metrics

CVSS 3.x Severity and Vector Strings:

NIST: [email protected]CVSS-B:5.3 MEDIUMVector:CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

CNA: [email protected]CVSS-B:6.8 MEDIUMVector:CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json	[email protected]	Vendor Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-99	Improper Control of Resource Identifiers ('Resource Injection')	[email protected]

Affected Products

Product	Versions
dovecot dovecot	< 2.4.4
CPE cpe:2.3:a:dovecot:dovecot:::::::: Remediation No remediation found in references.
open-xchange dovecot	< 3.1.5
CPE cpe:2.3:a:open-xchange:dovecot:::::pro:::* Remediation No remediation found in references.

Change History

4 change records found show changes

Date	Action	Recorded By
Jun 17, 2026	CVE Modified	[email protected]
Jun 17, 2026	CVE Modified	CISA-ADP
May 18, 2026	Initial Analysis	[email protected]
May 12, 2026	New CVE Received	[email protected]