CVE-2026-49178 in Windows
Summary
by MITRE • 07/14/2026
Heap-based buffer overflow in Active Directory Domain Services allows an authorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 07/15/2026
This vulnerability represents a critical heap-based buffer overflow within Active Directory Domain Services that enables remote code execution by authenticated attackers. The flaw exists in the memory management handling of domain services components, specifically when processing certain network requests or directory operations. Attackers exploiting this vulnerability can manipulate heap allocation patterns to overwrite adjacent memory regions, potentially leading to arbitrary code execution on affected domain controllers. The vulnerability is particularly concerning because it requires only authentication privileges within the domain, meaning an attacker who has obtained valid user credentials can leverage this weakness without needing elevated administrative rights.
The technical implementation of this buffer overflow occurs when Active Directory Domain Services processes malformed input data through its heap management functions. When legitimate users submit specific network requests or directory queries that trigger memory allocation routines, the system fails to properly validate input lengths against allocated buffer sizes. This allows attackers to overflow heap-allocated memory regions and potentially overwrite critical function pointers or return addresses within the execution stack. The vulnerability aligns with CWE-121 heap-based buffer overflow classification and represents a significant weakness in the memory safety mechanisms of Microsoft's directory services implementation.
The operational impact of this vulnerability extends beyond simple code execution capabilities to encompass complete domain compromise scenarios. Once an attacker successfully exploits this weakness, they can establish persistence within the domain environment, escalate privileges, and potentially move laterally across network segments. The attack surface includes all domain controller systems running vulnerable versions of Active Directory Domain Services, making it a prime target for enterprise-wide attacks. From an adversarial perspective, this vulnerability maps directly to ATT&CK technique T1078 legitimate credentials usage and T1566 credential access through network service exploitation, enabling attackers to maintain persistent access while operating within the trusted domain environment.
Organizations should implement immediate mitigations including applying Microsoft security patches as soon as they become available, implementing network segmentation to limit lateral movement capabilities, and monitoring for anomalous authentication patterns or unusual directory service requests. Additional defensive measures involve deploying intrusion detection systems that can identify malformed Active Directory traffic patterns and establishing privileged access management controls to reduce the attack surface. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches in enterprise directory services environments, as even authenticated attackers can leverage such flaws to achieve significant system compromise. Regular security assessments of domain controller configurations and memory safety practices should be implemented to identify similar vulnerabilities before they can be exploited by malicious actors.