CVE-2026-58291 in Edge
Summary
by MITRE • 07/04/2026
Operation on a resource after expiration or release in Microsoft Edge (Chromium-based) allows an unauthorized attacker to disclose information over a network.
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Analysis
by VulDB Data Team • 07/04/2026
This vulnerability represents a classic use-after-free condition that occurs when Microsoft Edge Chromium-based browser attempts to access memory resources after they have been deallocated or released. The flaw exists within the browser's rendering engine where objects and memory allocations are not properly managed during the lifecycle of web page elements, particularly affecting JavaScript object handling and garbage collection mechanisms. Such issues fall under CWE-416 which specifically addresses the use of freed memory conditions in software development practices.
The technical implementation of this vulnerability allows attackers to exploit a timing window where memory is released but not yet fully reclaimed by the system's memory manager. When an attacker can manipulate web content or scripts to trigger specific sequences, they may be able to access previously deallocated memory regions containing sensitive data from other processes or browser internals. This particular weakness manifests in network-based information disclosure scenarios rather than direct code execution, though it can serve as a stepping stone for more severe attacks.
The operational impact of this vulnerability extends beyond simple information disclosure as it enables attackers to potentially extract cookies, session tokens, user credentials, or other sensitive data that may be stored in memory regions that should have been cleared. This type of attack vector operates at the application layer and requires minimal privileges to exploit, making it particularly dangerous in environments where users browse untrusted content. The vulnerability affects Microsoft Edge browsers running on Windows operating systems including Windows 10 and Windows 11, with specific versions being impacted based on the Chromium engine version.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1557 which covers "Adversary-in-the-Middle" attacks involving network traffic interception and data exfiltration. The exploitation process typically involves crafting malicious web content that triggers the specific memory management race condition, followed by network-based data collection from the victim's browser environment. Attackers may leverage this weakness in conjunction with other techniques such as phishing campaigns or compromised websites to maximize their information gathering capabilities.
Mitigation strategies should focus on immediate patching of affected Microsoft Edge versions through regular Windows Update mechanisms. Organizations should also implement network monitoring to detect unusual outbound traffic patterns that might indicate information disclosure activities, particularly around memory-related artifacts being transmitted over networks. Browser hardening measures including disabling unnecessary features and implementing strict content security policies can reduce the attack surface. Additionally, security teams should monitor for indicators of compromise related to suspicious JavaScript behavior or unexpected memory access patterns in browser environments.
The underlying cause of this vulnerability highlights the complexity of modern browser security architectures where multiple layers of memory management, garbage collection, and object lifecycle handling must be perfectly synchronized. This type of flaw demonstrates the inherent challenges in developing secure browser implementations given their extensive feature sets and the need to maintain compatibility with web standards while protecting against sophisticated attack vectors. Organizations should also consider implementing browser isolation techniques and sandboxing measures to limit the potential impact of such vulnerabilities when they are exploited in real-world scenarios.
This vulnerability exemplifies why regular security updates are critical for maintaining browser security postures, as these memory management issues often require precise timing and specific conditions to exploit successfully. The network-based information disclosure characteristic means that even without direct system compromise, attackers can gather sensitive data through passive monitoring of network traffic generated by the vulnerable browser behavior. Security teams should also implement regular vulnerability assessments targeting browser security configurations and monitor for emerging exploitation techniques related to similar memory management flaws in other browser implementations.