CVE-2026-49174 in Windows
Summary
by MITRE • 07/14/2026
Missing authentication for critical function in Microsoft Windows DNS allows an authorized attacker to perform tampering locally.
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Analysis
by VulDB Data Team • 07/15/2026
This vulnerability represents a critical security flaw in Microsoft Windows Domain Name System implementation where insufficient authentication mechanisms exist for essential administrative functions. The weakness stems from the Windows DNS server service failing to properly validate user credentials before executing privileged operations, creating an avenue for authenticated attackers who have already gained system access to manipulate DNS records and configurations without additional authorization checks.
The technical nature of this vulnerability falls under CWE-284 which specifically addresses inadequate access control mechanisms, particularly when authentication is missing for critical functions within a system. Attackers exploiting this weakness can leverage their existing authorized access to perform unauthorized DNS modifications including record addition, deletion, or modification that could redirect network traffic to malicious endpoints. This represents a privilege escalation scenario where local access provides the foundation for more extensive network disruption and potential lateral movement.
The operational impact of this vulnerability extends beyond simple DNS manipulation as it enables attackers to establish persistent backdoors through DNS tunneling techniques or create authoritative points of failure that can compromise network availability and integrity. Network administrators may experience unauthorized changes to critical DNS infrastructure that could go undetected for extended periods, potentially leading to data exfiltration, man-in-the-middle attacks, or complete network isolation of legitimate services.
Organizations should implement comprehensive monitoring solutions that track DNS query patterns and record modifications to detect anomalous behavior indicative of this attack vector. Network segmentation combined with strict access controls and regular security audits can help mitigate the risk while maintaining operational continuity. The vulnerability aligns with several ATT&CK techniques including T1071.004 for application layer protocol: dns and T1566 for credential harvesting, making it particularly dangerous in environments where attackers have already established a foothold through other means.
Microsoft has addressed this issue through security updates that enforce proper authentication checks for DNS administrative functions, requiring explicit authorization before allowing critical operations to proceed. Organizations must ensure timely patch deployment across all Windows DNS server implementations and consider implementing additional network-level controls such as DNS sinkhole configurations and DNS query logging to maintain visibility into potential exploitation attempts while adhering to security best practices recommended by NIST SP 800-53 and ISO 27001 standards.