CVE-1999-0004 in Solaris
Summary
by MITRE
MIME buffer overflow in email clients, e.g. Solaris mailtool and Outlook.
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Analysis
by VulDB Data Team • 04/17/2026
The vulnerability identified as CVE-1999-0004 represents a critical buffer overflow condition affecting MIME (Multipurpose Internet Mail Extensions) processing in email client applications across multiple platforms including Solaris mailtool and Microsoft Outlook. This flaw occurs when email clients attempt to parse malformed MIME content that exceeds the allocated buffer space, creating an exploitable condition that can be leveraged by malicious actors to execute arbitrary code on vulnerable systems. The vulnerability specifically targets the parsing mechanism responsible for handling email attachments and encoded content that follows MIME standards, making it particularly dangerous in enterprise email environments where users frequently receive complex email messages.
The technical implementation of this buffer overflow stems from inadequate input validation and bounds checking within the MIME parsing libraries used by affected email clients. When processing email messages containing specially crafted malicious MIME headers or encoded content, the applications fail to properly validate the length of incoming data against predetermined buffer limits. This allows attackers to overwrite adjacent memory locations, potentially corrupting program execution flow and enabling code execution. The vulnerability manifests most severely in applications that do not implement proper stack canaries, memory protection mechanisms, or input sanitization routines that would normally prevent such overflows from being exploited. The flaw affects the core email processing functionality and can be triggered through simple email reception without requiring user interaction beyond opening the malicious message.
The operational impact of CVE-1999-0004 extends beyond individual system compromise to potentially affect entire email infrastructures within organizations. Attackers can leverage this vulnerability to gain unauthorized access to email servers, compromise user accounts, or establish persistent backdoors through the execution of malicious code. The vulnerability's presence in widely used applications like Microsoft Outlook means that successful exploitation could affect thousands of users simultaneously, particularly in corporate environments where email remains the primary communication channel. The attack vector is particularly insidious because it can be delivered through standard email protocols without requiring specialized knowledge or tools beyond crafting a malicious email message. Organizations may face significant disruption including data breaches, system downtime, and potential regulatory compliance violations when such vulnerabilities are exploited in production environments.
Mitigation strategies for CVE-1999-0004 require immediate application of vendor security patches and updates to address the underlying buffer overflow conditions in affected email clients. System administrators should implement network-level filtering to block suspicious email content and configure email clients with strict MIME parsing validation settings. The implementation of email security gateways and content filtering solutions can provide additional layers of protection by scanning incoming messages for malformed MIME content before delivery to end users. Organizations should also consider implementing runtime protection mechanisms such as stack protection features, address space layout randomization, and data execution prevention to reduce the exploitability of similar vulnerabilities. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar buffer overflow conditions in other email processing components. The vulnerability demonstrates the importance of adhering to secure coding practices and input validation as outlined in common weakness enumeration standards and highlights the need for comprehensive security testing of email processing libraries. This vulnerability serves as a foundational example of how improper memory management in email applications can create critical security risks that affect millions of users globally.