CVE-2010-0488 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 5.01 SP4, 6, 6 SP1, and 7 does not properly handle unspecified "encoding strings," which allows remote attackers to bypass the Same Origin Policy and obtain sensitive information via a crafted web site, aka "Post Encoding Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 05/04/2026
The vulnerability identified as CVE-2010-0488 represents a critical security flaw in Microsoft Internet Explorer versions 5.01 SP4, 6, 6 SP1, and 7 that specifically targets the browser's handling of encoding strings within web content. This weakness enables malicious actors to exploit a fundamental security mechanism designed to prevent unauthorized access to web resources across different origins. The issue stems from Internet Explorer's improper processing of unspecified encoding strings that occur during the parsing of web pages, creating a pathway for attackers to circumvent the browser's Same Origin Policy implementation. The Same Origin Policy serves as a cornerstone of web security by restricting how documents or scripts loaded from one origin can interact with resources from another origin, thereby preventing cross-site scripting attacks and information leakage between domains.
The technical nature of this vulnerability involves the browser's failure to properly validate and handle encoding specifications within web content, particularly when processing encoded strings that may contain embedded or hidden information. When Internet Explorer encounters malformed or unexpected encoding strings, it fails to properly isolate the content according to security boundaries, allowing attackers to craft malicious web pages that can access resources from different origins. This flaw operates at the core of how browsers interpret and process character encoding, specifically targeting the mechanisms that should prevent unauthorized cross-origin data access. The vulnerability is particularly concerning because it affects multiple versions of Internet Explorer spanning nearly a decade, indicating a persistent flaw in the browser's encoding handling mechanisms. This type of information disclosure vulnerability is classified under CWE-200, which covers "Information Exposure," and represents a specific instance of how improper input validation can lead to security policy bypasses.
The operational impact of this vulnerability extends far beyond simple information disclosure, as it provides attackers with the capability to execute sophisticated cross-site attacks that could compromise user data and system integrity. Attackers can leverage this weakness to construct malicious websites that can access cookies, session tokens, and other sensitive information from different domains, effectively breaking down the security barriers that separate user sessions and protected resources. The implications are particularly severe in enterprise environments where users may have access to multiple web applications with varying levels of security clearance, as the vulnerability could enable attackers to aggregate information across different security domains. This vulnerability aligns with ATT&CK technique T1071.004, which covers "Application Layer Protocol: DNS," and represents a form of protocol manipulation that exploits browser implementation gaps. The attack vector typically involves hosting malicious content on a compromised server or through social engineering techniques that trick users into visiting crafted web pages that exploit the encoding string handling flaw.
Mitigation strategies for CVE-2010-0488 require immediate action to address the underlying browser vulnerabilities, including prompt deployment of Microsoft security patches and updates that correct the encoding string handling behavior. Organizations should implement comprehensive browser security policies that restrict access to potentially malicious websites and enforce strict content security policies that limit cross-origin resource sharing. Network-level protections such as web application firewalls and content filtering systems can provide additional layers of defense by monitoring for suspicious encoding patterns and blocking access to known malicious sites. Users should be educated about the risks of visiting untrusted websites and the importance of keeping their browsers updated with the latest security patches. The vulnerability also underscores the importance of implementing robust input validation and encoding handling mechanisms in web applications, as proper server-side validation can help prevent attackers from exploiting browser-level weaknesses. Organizations should conduct regular security assessments to identify and remediate similar encoding-related vulnerabilities in their web applications and browser configurations. This vulnerability demonstrates the critical need for continuous security monitoring and patch management processes, as it affected multiple versions of Internet Explorer over an extended period, indicating that the flaw was not adequately addressed through initial security updates. The remediation approach must consider both immediate patch deployment and long-term security architecture improvements to prevent similar encoding-related vulnerabilities from emerging in future browser implementations.