CVE-2020-1558 in Windows
Summary
by MITRE
A remote code execution vulnerability exists when the Windows Jet Database Engine improperly handles objects in memory. An attacker who successfully exploited this vulnerability could execute arbitrary code on a victim system. An attacker could exploit this vulnerability by enticing a victim to open a specially crafted file. The update addresses the vulnerability by correcting the way the Windows Jet Database Engine handles objects in memory.
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Analysis
by VulDB Data Team • 02/24/2026
The vulnerability identified as CVE-2020-1558 represents a critical remote code execution flaw within the Windows Jet Database Engine component. This database engine serves as the foundation for various Microsoft applications including Access, Outlook, and numerous third-party software solutions that rely on jet database files. The vulnerability stems from improper memory handling when processing database objects, creating a pathway for malicious actors to execute arbitrary code on affected systems. The flaw specifically manifests during the parsing and manipulation of memory objects within the Jet Database Engine, where insufficient validation allows crafted malicious inputs to trigger unintended code execution sequences.
This vulnerability operates through a classic buffer over-read condition that falls under CWE-125, where the engine fails to properly validate memory boundaries when processing specially crafted database files. The attack vector requires social engineering to convince victims to open maliciously crafted files, typically in formats such as .mdb or .accdb database files. When these files are opened, the Jet Database Engine attempts to process malformed memory objects without proper boundary checks, leading to memory corruption that can be exploited to inject and execute malicious code with the privileges of the victim user. The vulnerability demonstrates characteristics consistent with the ATT&CK technique T1203, where adversaries leverage application flaws to execute code remotely.
The operational impact of CVE-2020-1558 extends beyond simple code execution, as it provides attackers with potential access to sensitive data, system resources, and the ability to establish persistence mechanisms. Since the vulnerability affects core database functionality used across multiple Microsoft applications, the attack surface is extensive and includes both desktop and server environments. The exploitability requires user interaction through file opening, making it particularly dangerous in targeted phishing campaigns or when users encounter malicious attachments in email communications. Organizations running systems with Microsoft Office, Access, or other applications that utilize the Jet Database Engine are at risk, particularly when these applications are configured to automatically open or process database files from untrusted sources.
Mitigation strategies should focus on immediate patch deployment through Microsoft's security updates, which correct the memory handling behavior in the Jet Database Engine. Organizations should also implement restrictive file execution policies, disable automatic opening of database files, and employ sandboxing techniques for handling untrusted content. Network-level controls including email filtering and web proxy configurations can help prevent the delivery of malicious database files. Additionally, security monitoring should be enhanced to detect unusual database file processing activities and memory access patterns that may indicate exploitation attempts. The vulnerability highlights the importance of regular security updates and proper application hardening practices, as it represents a fundamental flaw in how database engines handle memory management and input validation.