CVE-2026-61936 in Windows
Summary
by MITRE • 08/11/2026
Missing authorization in Windows Defender Firewall Service allows an authorized attacker to bypass a security feature locally.
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Analysis
by VulDB Data Team • 08/12/2026
The vulnerability stems from insufficient authorization checks within the Windows Defender Firewall service implementation, creating a critical security gap that enables authenticated attackers to circumvent local firewall protections. This weakness resides in the service's inability to properly validate user permissions before processing firewall configuration requests, allowing malicious actors with local access to manipulate network security policies without proper administrative privileges.
The technical flaw manifests through improper access control mechanisms within the Windows Defender Firewall service architecture, where the system fails to enforce mandatory access controls when processing firewall rule modifications. Attackers can exploit this by leveraging legitimate user accounts with standard privileges to execute unauthorized firewall configuration changes that should typically require administrator-level permissions. This represents a classic authorization bypass vulnerability that violates fundamental security principles of least privilege and principle of least privilege enforcement.
The operational impact of this vulnerability extends beyond simple firewall manipulation, as it provides attackers with persistent local access to network protection mechanisms that are designed to prevent unauthorized communications. An attacker with local access can disable firewall protections, create backdoor rules, or modify existing configurations to allow malicious traffic while blocking legitimate security monitoring. The vulnerability essentially undermines the integrity of the local network security posture by enabling unauthorized modification of critical system defenses.
This weakness aligns with CWE-285, which addresses improper authorization in software implementations, and maps to ATT&CK technique T1068, which covers local privilege escalation through service manipulation. The vulnerability enables attackers to establish persistence and maintain access while evading network-based detection mechanisms that rely on proper firewall configurations.
Mitigation strategies should focus on implementing robust access control validation within the Windows Defender Firewall service, ensuring that all configuration changes require appropriate authorization levels before execution. System administrators should enforce mandatory access controls through proper user privilege management, regularly audit firewall configurations, and implement monitoring solutions to detect unauthorized firewall modifications. Additionally, organizations should maintain up-to-date security patches and consider implementing additional layers of defense such as application control policies and integrity checking mechanisms to prevent exploitation of this authorization bypass vulnerability.