CVE-2026-62782 in Windows
Summary
by MITRE • 08/11/2026
Out-of-bounds read in Windows SMB Client allows an unauthorized attacker to disclose information over a network.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability represents a critical security flaw in the Windows Server Message Block protocol implementation that affects network communication between clients and servers. The out-of-bounds read condition occurs when the SMB client processes malformed or specially crafted network packets, allowing an attacker to access memory locations beyond the intended buffer boundaries. This type of vulnerability falls under the common weakness enumeration CWE-125 which specifically addresses out-of-bounds read errors that can lead to information disclosure and potential system compromise. The flaw exists in the SMB client component's packet parsing logic where insufficient input validation permits malicious data structures to trigger memory access violations that reveal sensitive information from system memory.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with potential access to confidential data, credentials, or system internals that could be leveraged for further exploitation. Network-based attacks can be executed without requiring authentication, making the vulnerability particularly dangerous in environments where SMB traffic flows between systems. The attack vector typically involves sending specially crafted SMB packets to a vulnerable Windows system, which then processes these packets through the flawed client implementation. According to ATT&CK framework, this vulnerability maps to technique T1071.004 for application layer protocol usage and T1068 for exploit for privilege escalation through remote code execution possibilities that may stem from information disclosure.
The technical exploitation of this vulnerability requires understanding of SMB protocol internals and memory management patterns within Windows operating systems. Attackers can potentially extract valuable information such as kernel memory contents, credential caches, or other sensitive data structures that are not properly protected from unauthorized access. The vulnerability affects multiple Windows versions including server editions and desktop operating systems that utilize SMB client functionality for network file sharing and resource access. Security researchers have identified that the flaw manifests when the SMB client attempts to parse certain packet headers or data structures without proper boundary checks, leading to memory access violations that can be exploited to gather system information.
Organizations should implement immediate mitigations including applying Microsoft security patches as soon as they become available, disabling SMBv1 protocol if not required for legacy system compatibility, and implementing network segmentation controls to limit exposure. Network monitoring solutions should be configured to detect anomalous SMB traffic patterns that may indicate exploitation attempts. The vulnerability demonstrates the importance of robust input validation in network protocols and highlights how seemingly minor implementation flaws can create significant security risks. Organizations using Windows systems must also consider implementing additional security controls such as firewall rules restricting SMB port access, endpoint detection and response solutions, and regular vulnerability assessments to identify potential exposure points. According to industry best practices for secure coding standards, this type of vulnerability could have been prevented through proper boundary checking mechanisms and comprehensive input validation procedures that align with secure development lifecycle requirements.