CVE-2026-84550 in macOS
Summary
by MITRE • 09/15/2026
A race condition was addressed with additional validation. This issue is fixed in macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7. An app may be able to cause unexpected system termination.
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Analysis
by VulDB Data Team • 09/15/2026
The vulnerability described involves a race condition within the operating system's core processes, specifically addressed through enhanced validation mechanisms in recent updates for macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. A race condition occurs when two or more threads of execution access shared data concurrently without proper synchronization, leading to unpredictable behavior depending on the timing of these accesses. In this context, an application can exploit a window where system resources are being accessed or modified by multiple processes simultaneously, allowing it to manipulate state in ways that were not anticipated by the original design. This flaw represents a classic concurrency bug often categorized under CWE-362, which covers race conditions involving simultaneous access and modification of shared data.
The operational impact of this vulnerability is significant as it allows an unprivileged application to trigger unexpected system termination. By carefully crafting requests or actions that exploit the timing gap in validation checks, a malicious actor can cause critical system components to fail catastrophically. This results in a denial-of-service condition where the entire operating system may crash or reboot unexpectedly. Such instability not only disrupts user productivity but also poses potential security risks if the termination occurs during sensitive operations like authentication or data encryption processes. The ability to force an unexpected shutdown undermines the reliability and availability guarantees expected from enterprise-grade operating systems, making it a high-severity issue for environments requiring continuous uptime.
From a threat modeling perspective, this vulnerability aligns with MITRE ATT&CK techniques related to resource exhaustion and system service disruption. Attackers can leverage such flaws in automated scripts or malware to degrade the performance of target machines without needing elevated privileges initially. The exploitation typically involves rapid successive calls to specific APIs or kernel interfaces that trigger the race condition before the additional validation logic introduced by Apple can effectively mitigate it. This highlights the importance of robust synchronization primitives and strict access controls within system-level code to prevent such timing-based exploits from succeeding.
Mitigation strategies primarily rely on applying the provided software updates which include the necessary patches for macOS Golden Gate 27, Sequoia 15.8, and Tahoe 26.7. These updates implement stricter validation checks that close the race window by ensuring atomic operations or proper locking mechanisms are in place during critical system transitions. Administrators should prioritize patching affected systems to restore stability and prevent potential denial-of-service attacks. Additionally, developers building applications for these platforms should review their code for any concurrent access patterns that might inadvertently trigger similar conditions, adhering to secure coding practices that emphasize thread safety and proper resource management. Regular security audits and static analysis tools can help identify such concurrency issues early in the development lifecycle before they reach production environments.