CVE-2020-1555 in Edge
Summary
by MITRE
A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Microsoft Edge (HTML-based). The vulnerability could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft Edge (HTML-based) and then convince a user to view the website. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability. The security update addresses the vulnerability by modifying how the scripting engine handles objects in memory.
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Analysis
by VulDB Data Team • 02/24/2026
This vulnerability represents a critical remote code execution flaw in Microsoft Edge's HTML-based scripting engine that operates at the memory management level. The issue stems from improper handling of objects within memory structures, creating a condition where memory corruption can occur during normal script execution. When exploited, this flaw allows attackers to manipulate memory in ways that enable arbitrary code execution with the privileges of the currently logged-on user. The vulnerability specifically affects the scripting engine's memory management routines, which are fundamental to how Edge processes HTML and JavaScript content. This type of memory corruption vulnerability is particularly dangerous because it can be triggered through standard web browsing activities, making it highly exploitable in real-world scenarios.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and potentially CWE-787, representing out-of-bounds write vulnerabilities. From an operational perspective, the attack vector is highly practical as it can be delivered through malicious websites, compromised web pages, or even legitimate sites that have been infiltrated with malicious content. The exploit chain typically begins with a user visiting a specially crafted webpage that contains malicious JavaScript code designed to trigger the memory corruption. The attacker can leverage this vulnerability through the attacker control flow (ATT&CK T1203) and privilege escalation techniques (ATT&CK T1068) to gain system-level access. The vulnerability's impact extends beyond simple code execution to full system compromise when users have administrative privileges, as the exploitation can result in complete system takeover through account creation and data manipulation capabilities.
The security remediation implemented by Microsoft addresses the core memory handling issue by modifying how the scripting engine manages object allocation and deallocation in memory. This fix involves strengthening memory management routines to prevent the specific corruption patterns that enable exploitation. Organizations should prioritize immediate deployment of the security update as the vulnerability has a high exploitability score and can be leveraged for complete system compromise. The mitigation strategy should include network-based protections such as web application firewalls and content filtering solutions to detect and block malicious content, while also implementing user education to avoid visiting suspicious websites. Regular security assessments should verify that the patch has been properly applied across all affected systems, and monitoring solutions should be configured to detect anomalous memory access patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of secure memory management practices in browser environments and highlights the need for continuous security testing of core engine components.