CVE-2006-5162 in Internet Explorer
Summary
by MITRE
wininet.dll in Microsoft Internet Explorer 6.0 SP2 and earlier allows remote attackers to cause a denial of service (unhandled exception and crash) via a long Content-Type header, which triggers a stack overflow.
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Analysis
by VulDB Data Team • 04/23/2026
The vulnerability identified as CVE-2006-5162 represents a critical stack overflow flaw within the wininet.dll component of Microsoft Internet Explorer versions 6.0 Service Pack 2 and earlier. This issue manifests when the browser encounters a malformed Content-Type header in HTTP responses that exceeds normal parameter limits, creating an exploitable condition that can be leveraged by remote attackers to disrupt service availability. The vulnerability specifically affects the handling of HTTP response headers within the Internet Explorer web browser's core networking library, which is responsible for managing internet connectivity and data transfer operations.
The technical implementation of this vulnerability stems from inadequate input validation within the wininet.dll library's parsing routine for Content-Type headers. When Internet Explorer processes an HTTP response containing an excessively long Content-Type header, the parsing function fails to properly manage memory allocation for string processing operations, leading to a stack buffer overflow condition. This overflow occurs because the application does not enforce proper bounds checking on header length parameters, allowing maliciously crafted headers to exceed allocated stack space and overwrite adjacent memory segments. The flaw operates at the application layer and requires no special privileges or authentication to exploit, making it particularly dangerous for widespread deployment.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it represents a fundamental security weakness that could potentially be chained with other exploits to achieve more severe outcomes. When exploited successfully, the stack overflow causes an unhandled exception that results in an immediate browser crash and system instability. This behavior aligns with CWE-121, which describes stack-based buffer overflow conditions, and demonstrates how improper memory management can lead to complete application compromise. The vulnerability's remote exploitability means that attackers can trigger the condition through web-based attacks without requiring physical access to target systems, making it particularly attractive for large-scale attacks against vulnerable user populations.
Organizations affected by this vulnerability should implement immediate mitigations including deployment of Microsoft security patches, network-based filtering of suspicious Content-Type headers, and browser hardening measures. The recommended remediation approach involves applying the official Microsoft security update that addresses the buffer overflow condition in wininet.dll, while also implementing network-level controls to detect and block malformed HTTP responses. From an operational security perspective, this vulnerability highlights the importance of maintaining up-to-date software patches and implementing defense-in-depth strategies that include web application firewalls and intrusion detection systems. The ATT&CK framework categorizes this vulnerability under the T1203 technique for "Exploitation for Client Execution" and T1499 for "Endpoint Denial of Service," emphasizing its potential for both service disruption and broader exploitation opportunities. Additionally, organizations should consider implementing browser isolation techniques and restricting access to potentially malicious web content through security policies and network segmentation measures to prevent unauthorized exploitation of this and similar vulnerabilities.