CVE-2010-1127 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6 and 7 does not initialize certain data structures during execution of the createElement method, which allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via crafted JavaScript code, as demonstrated by setting the (1) outerHTML or (2) value property of an object returned by createElement.
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Analysis
by VulDB Data Team • 05/03/2026
The vulnerability described in CVE-2010-1127 represents a critical flaw in Microsoft Internet Explorer 6 and 7 browsers that stems from improper initialization of data structures during the execution of the createElement method. This issue falls under the category of improper initialization vulnerabilities, which are commonly classified as CWE-459 and CWE-665 in the Common Weakness Enumeration framework. The flaw manifests when the browser processes JavaScript code that utilizes the createElement method to generate DOM elements, specifically when these elements are subsequently manipulated through the outerHTML or value properties. The root cause lies in the browser's failure to properly initialize memory structures that should be allocated and configured before the method execution completes, creating a scenario where subsequent operations on these uninitialized objects can trigger unexpected behavior.
The operational impact of this vulnerability is significant as it enables remote attackers to execute denial of service attacks against vulnerable systems. When an attacker crafts malicious JavaScript code that exploits this weakness, the browser encounters a NULL pointer dereference during the processing of the createElement method's output. This type of error occurs because the browser attempts to access memory locations that have not been properly allocated or initialized, leading to application crashes and system instability. The vulnerability specifically targets the interaction between the createElement method and the outerHTML or value properties, which are commonly used in web applications for dynamic content manipulation and DOM tree modifications. This exploitation vector is particularly dangerous because it can be triggered through standard web browsing activities without requiring any special privileges or user interaction beyond visiting a malicious website.
The technical exploitation of this vulnerability demonstrates the importance of proper memory management and initialization practices in browser implementations. According to the MITRE ATT&CK framework, this represents a technique that could be categorized under T1499.004 - Endpoint Denial of Service, where adversaries leverage application-level vulnerabilities to disrupt services. The flaw essentially creates a condition where the browser's JavaScript engine fails to properly establish the necessary object state before allowing operations on the created elements. This misconfiguration can be leveraged by attackers to force browser crashes, which not only disrupts user experience but can also potentially be used as a stepping stone for more sophisticated attacks. The vulnerability's impact extends beyond simple service disruption as it represents a fundamental breakdown in the browser's object lifecycle management, where objects are created but not properly initialized for subsequent operations.
Mitigation strategies for this vulnerability primarily focus on immediate browser updates and patches provided by Microsoft, as well as implementing security measures at the network and application level. Organizations should ensure that all Internet Explorer 6 and 7 installations are updated with the relevant security patches released by Microsoft, as these versions are no longer supported and contain numerous other security vulnerabilities. Network administrators can implement content filtering solutions that detect and block known malicious JavaScript patterns, while application developers should validate all user inputs and implement proper error handling to prevent exploitation. The vulnerability also highlights the importance of browser sandboxing and memory protection mechanisms that can limit the impact of such flaws. Additionally, security professionals should consider implementing browser hardening configurations that restrict the execution of potentially dangerous JavaScript operations, particularly those involving DOM manipulation methods that could trigger similar initialization issues. Regular security assessments and penetration testing should include evaluation of browser-specific vulnerabilities to identify and remediate similar weaknesses in legacy browser implementations.