CVE-2026-56194
Summary
by MITRE • 07/14/2026
Heap-based buffer overflow in Windows Network File System allows an authorized attacker to elevate privileges over a network.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 07/14/2026
A heap-based buffer overflow vulnerability exists within the Windows Network File System implementation that enables authenticated attackers to achieve privilege escalation through remote network access. This flaw resides in the handling of specific network file system requests where insufficient bounds checking occurs during memory allocation and data copying operations within heap memory structures. The vulnerability manifests when legitimate network clients interact with file system services, particularly during file access or directory enumeration operations that trigger the affected code path.
The technical mechanism behind this vulnerability involves improper validation of input parameters received through network file system protocols such as SMB or NFS implementations. When processing structured network requests containing oversized data payloads or malformed parameter values, the system allocates heap memory blocks without adequate size verification before copying user-supplied data into these buffers. This condition creates a situation where attacker-controlled data can overwrite adjacent heap memory locations, potentially corrupting critical data structures or function pointers that govern privilege management within the file system service.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and unauthorized data access across networked environments. An authenticated attacker positioned within the network can exploit this weakness to elevate their privileges from standard user level to administrative or system-level access, thereby gaining control over shared resources, file systems, and potentially entire network infrastructure. The attack vector requires only network connectivity and valid authentication credentials, making it particularly dangerous in enterprise environments where network file sharing is prevalent.
Security implications of this vulnerability align with CWE-121 Heap-based Buffer Overflow classification, which specifically addresses buffer overflow conditions occurring in heap memory allocations. The ATT&CK framework categorizes this as privilege escalation through exploitation of software vulnerabilities under the technique ID T1068, where adversaries leverage system weaknesses to gain higher-level permissions. This vulnerability represents a critical security gap that directly impacts Microsoft Windows operating systems and network file sharing services, particularly affecting enterprise environments relying heavily on centralized file storage solutions.
Mitigation strategies should include immediate deployment of Microsoft security patches addressing the specific heap overflow condition within network file system implementations. Network administrators should implement strict access controls limiting unnecessary network file sharing access and establish monitoring protocols to detect anomalous file system activity patterns that may indicate exploitation attempts. Additionally, deploying intrusion detection systems capable of identifying malicious network requests targeting known vulnerable endpoints and maintaining comprehensive network segmentation can significantly reduce the attack surface and potential impact of such vulnerabilities.