CVE-2026-64691 in macOS
Summary
by MITRE • 07/28/2026
A buffer overflow was addressed with improved size validation. This issue is fixed in macOS Tahoe 26.6. An app may be able to cause unexpected system termination.
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Analysis
by VulDB Data Team • 07/28/2026
This vulnerability represents a classic buffer overflow condition that was resolved through enhanced size validation mechanisms within the macOS Tahoe 26.6 operating system release. The flaw existed in the system's memory management controls where insufficient bounds checking allowed malicious applications to write data beyond allocated memory buffers. Such conditions typically arise when software fails to properly validate input lengths or array sizes before processing user-supplied data, creating opportunities for attackers to overwrite adjacent memory locations. The vulnerability falls under CWE-121, which specifically addresses stack-based buffer overflow conditions, and may also relate to CWE-787 for out-of-bounds write scenarios that can lead to arbitrary code execution or system instability.
The operational impact of this vulnerability extends beyond simple application crashes to potentially compromise entire system stability. When an attacker successfully exploits this buffer overflow, they can cause unexpected system termination through controlled memory corruption that forces the operating system to crash or reboot unexpectedly. This type of exploitation aligns with ATT&CK technique T1499.001, which covers system shutdown/reboot attacks, and could also enable more sophisticated attacks through code execution in kernel space. The vulnerability particularly affects applications that process untrusted input data such as file parsing, network packet handling, or user interface element processing where buffer boundaries are not properly enforced.
The fix implemented in macOS Tahoe 26.6 addresses this issue through enhanced size validation controls that enforce strict bounds checking on all memory allocation operations. This mitigation approach follows security best practices outlined in the CERT Secure Coding Standards, specifically addressing the need for proper input validation and memory boundary enforcement. The update likely incorporates runtime checks that monitor buffer access patterns and reject operations that exceed predetermined size limits. Organizations should prioritize immediate deployment of this patch across their macOS environments as the vulnerability could be exploited by malicious applications to cause denial of service conditions or potentially escalate privileges through kernel-level memory corruption attacks.
The broader implications of this vulnerability highlight the critical importance of robust memory safety controls in modern operating systems, particularly given the increasing sophistication of attack vectors targeting system stability and reliability. Regular security updates and patch management processes become essential defensive measures against such vulnerabilities that can be exploited to compromise system availability and integrity. System administrators should monitor for any signs of unexpected system termination or crashes that could indicate exploitation attempts, while also implementing additional security controls such as application sandboxing and privilege separation to limit potential damage from successful attacks. The vulnerability demonstrates how seemingly simple memory management flaws can create significant operational risks when exploited in the context of modern operating system architectures where multiple applications interact with shared kernel resources.