CVE-2026-70339 in Edge
Summary
by MITRE • 08/11/2026
Access of resource using incompatible type ('type confusion') in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 08/11/2026
Type confusion vulnerabilities represent a critical class of software defects that occur when a program uses a variable or object in a manner inconsistent with its actual data type, creating opportunities for attackers to manipulate memory structures and execute arbitrary code. In the context of Microsoft Edge Chromium-based browsers, this specific vulnerability manifests when the browser's rendering engine encounters resources that are processed using incompatible data types, leading to unpredictable behavior that can be exploited by remote adversaries. The flaw typically arises in scenarios where the browser's JavaScript engine or rendering components fail to properly validate type information during runtime operations, particularly when handling complex web content or user-supplied data. This type of vulnerability falls under the CWE-479 category which specifically addresses the use of incompatible types in resource access operations and is classified as a memory safety issue that can lead to privilege escalation and remote code execution.
The exploitation of this type confusion vulnerability in Microsoft Edge enables attackers to craft malicious web pages or content that, when rendered by the browser, triggers the flawed type handling logic. The attack surface includes various web technologies such as web assembly, javascript objects, and DOM manipulation operations where type information may be improperly managed or validated. When an attacker successfully exploits this weakness, they can manipulate memory layouts, overwrite critical data structures, or redirect execution flow to malicious code that has been injected into the browser process. This vulnerability is particularly dangerous in network-based attacks because it requires no local privileges and can be delivered through standard web browsing activities, making it a prime target for phishing campaigns or compromised websites.
From an operational impact perspective, this vulnerability compromises the fundamental security model of modern web browsers by allowing remote code execution without user interaction. The attack can result in complete system compromise when users visit malicious websites, as the browser process typically runs with elevated privileges to handle web content securely. Security professionals should note that the exploitability of such vulnerabilities is heightened when the target environment includes older versions of the browser or when users have administrative rights on their systems. The vulnerability's network accessibility means that attackers can leverage it at scale through compromised websites, social engineering campaigns, or by directly targeting vulnerable browser installations. According to attack patterns documented in the mitre ATT&CK framework, this type of vulnerability maps closely to techniques involving remote code execution through web browsers and can be used as a initial access vector for more sophisticated attacks.
Mitigation strategies for this type confusion vulnerability should include immediate deployment of Microsoft security updates and patches that address the specific type handling flaws in the browser's rendering engine. Organizations should implement browser hardening measures such as enabling sandboxing features, restricting access to sensitive system resources, and configuring content security policies to limit potential exploitation vectors. Network defenders should monitor for suspicious web traffic patterns and consider implementing web application firewalls or proxy services that can detect and block malicious content before it reaches user browsers. Regular vulnerability assessments of browser installations and automated patch management systems are essential to prevent exploitation attempts, as the window between vulnerability disclosure and successful attacks is often very short in modern threat landscapes. Additionally, security awareness training for end users remains critical since social engineering campaigns often leverage these vulnerabilities to gain initial access to target systems through user interaction with malicious web content.