CVE-2006-0709 in Metamail
Summary
by MITRE
Buffer overflow in Metamail 2.7-50 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via e-mail messages with a long boundary attribute, a different vulnerability than CVE-2004-0105.
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Analysis
by VulDB Data Team • 06/22/2025
The vulnerability identified as CVE-2006-0709 represents a critical buffer overflow flaw in Metamail version 2.7-50 that manifests when processing email messages containing excessively long boundary attributes. This issue specifically affects the email handling capabilities of Metamail, which serves as a mail user agent for processing various email formats including MIME messages. The flaw arises from insufficient input validation and boundary checking within the application's parsing mechanism for email message boundaries, creating an exploitable condition that can be triggered through crafted email payloads.
The technical implementation of this vulnerability stems from the application's failure to properly validate the length of boundary attributes in MIME email messages. When Metamail encounters an email with an unusually long boundary string, it attempts to process this data without adequate bounds checking, leading to memory corruption that can result in either application crash or potential code execution. This buffer overflow occurs at the parsing layer where the application reads boundary identifiers from email headers, and the insufficient memory management creates a condition where attacker-controlled input can overwrite adjacent memory locations. The vulnerability operates under the common weakness pattern classified as CWE-121, which deals with stack-based buffer overflow conditions, and represents a classic example of unsafe string handling in legacy email processing software.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable remote code execution, making it particularly dangerous for email server environments and corporate email clients. Attackers can craft specially formatted email messages with maliciously long boundary attributes that, when processed by vulnerable Metamail installations, trigger the buffer overflow condition. The consequences include complete application compromise, system instability, and potential unauthorized access to email data. Organizations using Metamail for email processing face significant risk exposure, especially in environments where email filtering and processing occur without proper input sanitization. This vulnerability aligns with ATT&CK technique T1190, which covers exploitation of remote services through email-based attacks, and represents a persistent threat vector that could be leveraged for broader network compromise.
Mitigation strategies for CVE-2006-0709 require immediate action to update or replace vulnerable Metamail installations with patched versions or alternative email processing solutions. System administrators should implement email filtering rules that sanitize boundary attributes and limit the length of email headers to prevent exploitation. Network-based protections including email gateway filtering and content inspection can help detect and block malicious email payloads before they reach vulnerable endpoints. The vulnerability demonstrates the importance of input validation and memory safety practices in email processing applications, and organizations should consider implementing defensive measures such as stack canaries, address space layout randomization, and heap-based buffer overflow protections. Additionally, regular security assessments of email infrastructure and comprehensive patch management programs are essential for maintaining protection against similar vulnerabilities in legacy email processing systems.