CVE-2026-56178 in Defender for Endpoint for Mac
Summary
by MITRE • 07/14/2026
Time-of-check time-of-use (toctou) race condition in Microsoft Defender for Endpoint allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 07/15/2026
A time-of-check time-of-use race condition vulnerability exists within Microsoft Defender for Endpoint that enables authorized attackers to escalate privileges locally through a carefully orchestrated sequence of operations. This vulnerability stems from the improper handling of file access permissions during the verification and utilization phases of security checks, creating a temporal window where malicious actors can manipulate system state between the point of validation and actual execution.
The technical flaw manifests when Defender for Endpoint performs permission checks on specific files or directories and subsequently accesses those same resources without revalidating access controls. During this brief interval, an attacker with legitimate user privileges can replace or modify target files with malicious counterparts, causing the privileged defender process to execute unintended code with elevated permissions. This pattern aligns with common race condition vulnerabilities classified under CWE-367 and represents a classic example of improper resource management in security-critical systems.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with persistent access to system resources that would otherwise remain protected. Once elevated, malicious actors can manipulate endpoint security configurations, disable protective measures, or establish backdoors within the system. The attack vector requires only authorized user access, making it particularly dangerous in environments where standard user accounts have broad network permissions or where credential compromise occurs through social engineering attacks.
Mitigation strategies should focus on immediate patching of affected Microsoft Defender for Endpoint versions while implementing additional security controls such as file integrity monitoring and privilege separation mechanisms. Organizations should also consider applying the principle of least privilege to reduce the attack surface available to potential adversaries. The vulnerability demonstrates how seemingly minor implementation flaws in security software can create significant escalation opportunities, reinforcing the importance of rigorous code review processes and adherence to secure coding practices aligned with NIST cybersecurity frameworks.
Defender for Endpoint implementations should undergo comprehensive security audits to identify similar race condition patterns that might exist across other system components. Attackers leveraging such vulnerabilities typically follow the MITRE ATT&CK framework's privilege escalation tactics, specifically targeting process injection and credential manipulation techniques that can be facilitated through these temporal inconsistencies in access control validation. The remediation process must include both immediate vendor patches and long-term architectural improvements to prevent similar issues from emerging in future security implementations.