Open-Xchange OX Dovecot Pro up to 2.4.0/3.1.0 resource injection

Summaryinfo

A vulnerability identified as problematic has been detected in Open-Xchange OX Dovecot Pro up to 2.4.0/3.1.0. The impacted element is an unknown function. The manipulation leads to resource injection. This vulnerability is traded as CVE-2026-33603. Access to the local network is required for this attack to succeed. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Open-Xchange OX Dovecot Pro up to 2.4.0/3.1.0 and classified as problematic. This issue affects some unknown functionality. The manipulation with an unknown input leads to a resource injection vulnerability. Using CWE to declare the problem leads to CWE-99. The product receives input from an upstream component, but it does not restrict or incorrectly restricts the input before it is used as an identifier for a resource that may be outside the intended sphere of control. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at documentation.open-xchange.com. The identification of this vulnerability is CVE-2026-33603 since 03/23/2026. The exploitation is known to be difficult. The attack can only be initiated within the local network. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 318856 (Debian dla-4617 : dovecot-auth-lua - security update), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (318856) and EUVD (EUVD-2026-29468). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Mail Server Software

Vendor

• Open-Xchange

Name

• OX Dovecot Pro

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4.0
• 3.0
• 3.1.0

License

• open-source

Website

• Vendor: https://www.open-xchange.com/

CPE 2.3info

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CPE 2.2info

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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