Use-After-Free Vulnerability in Open-Xchange Dovecot Mail Server

CVE-2026-42007

What is CVE-2026-42007?

CVE-2026-42007 is a serious vulnerability identified in the Open-Xchange Dovecot Mail Server, which is primarily used for email hosting and management in various organizations. This vulnerability stems from a use-after-free flaw in the mail editing code that can be exploited by an attacker with valid credentials. By utilizing a Sieve script with the editheader extension, an attacker can manipulate email headers to trigger this flaw. This exploitation results in writing memory contents beyond the allocated buffer, potentially causing a memory leak and allowing for memory corruption during the email delivery process. Such behavior can disrupt operations by crashing the delivery process and may lead to arbitrary code execution with the privileges of the affected process, posing a significant risk to the integrity and security of email communications within an organization.

Potential impact of CVE-2026-42007

1. Arbitrary Code Execution: The vulnerability could allow an attacker to execute arbitrary code in the context of the mail delivery process. This could enable unauthorized actions within the server environment, leading to further exploitation and compromise of sensitive organizational data.

2. Service Disruption: The potential to crash the mail delivery process can lead to significant service outages. Organizations relying on Dovecot for email communication may experience interruptions that affect their day-to-day operations and communication efficiency.

3. Memory Corruption Risks: With the ability to manipulate memory beyond allocated boundaries, this vulnerability raises risks associated with memory corruption. Exploitation can undermine the stability and security of the system, leading to broader impacts on overall system integrity and vulnerabilities to further attacks.

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