CVE-2006-5559 in Data Access Components
Summary
by MITRE
The Execute method in the ADODB.Connection 2.7 and 2.8 ActiveX control objects (ADODB.Connection.2.7 and ADODB.Connection.2.8) in the Microsoft Data Access Components (MDAC) 2.5 SP3, 2.7 SP1, 2.8, and 2.8 SP1 does not properly track freed memory when the second argument is a BSTR, which allows remote attackers to cause a denial of service (Internet Explorer crash) and possibly execute arbitrary code via certain strings in the second and third arguments.
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Analysis
by VulDB Data Team • 04/25/2026
The vulnerability described in CVE-2006-5559 represents a critical memory corruption flaw within Microsoft Data Access Components that affects ActiveX control implementations. This issue specifically targets the ADODB.Connection 2.7 and 2.8 objects where the Execute method fails to properly manage memory allocation and deallocation processes when handling BSTR (Basic String) parameters. The flaw manifests when the second argument is processed as a BSTR type, creating conditions where freed memory references become accessible to malicious input, leading to potential exploitation scenarios.
The technical nature of this vulnerability stems from improper memory management practices within the MDAC component's ActiveX implementation. When the Execute method processes strings in the second and third arguments, the system does not adequately track memory that has been freed, creating a situation where attackers can manipulate input data to trigger memory corruption. This memory handling deficiency allows for both denial of service conditions and potential code execution, making it particularly dangerous in web browser environments where ActiveX controls are commonly executed.
The operational impact of this vulnerability extends beyond simple system instability to encompass serious security implications. Remote attackers can leverage this flaw to crash Internet Explorer browsers through carefully crafted malicious strings, causing denial of service attacks that disrupt legitimate user activities. More concerning is the potential for arbitrary code execution, which would allow attackers to gain unauthorized access to affected systems, execute malicious payloads, or establish persistent access points. The vulnerability affects multiple versions of MDAC including 2.5 SP3, 2.7 SP1, 2.8, and 2.8 SP1, indicating a widespread exposure across various Microsoft data access implementations.
From a cybersecurity perspective, this vulnerability aligns with CWE-122 (Heap Overflow) and CWE-125 (Out-of-bounds Read) categories, representing heap-based memory corruption issues that can lead to privilege escalation and system compromise. The attack surface is particularly concerning given that ActiveX controls are frequently executed within web browsers, making this vulnerability exploitable through web-based attacks. According to ATT&CK framework, this vulnerability maps to T1059.007 (Command and Scripting Interpreter: Windows Command Shell) and T1203 (Exploitation for Client Execution) categories, as it enables attackers to execute arbitrary code on target systems through browser-based exploitation.
Mitigation strategies for CVE-2006-5559 require immediate patch management and system hardening measures. Microsoft released security updates addressing this vulnerability through Windows Update and security bulletin MS06-071, which should be deployed immediately across all affected systems. Organizations should implement browser security restrictions, disable ActiveX controls where possible, and employ application whitelisting to prevent exploitation. Network segmentation and intrusion detection systems can help identify exploitation attempts, while regular security assessments should verify that all MDAC components are properly updated and that no legacy vulnerable versions remain in production environments.