External risk intelligence

macOS Integer Overflow Leads to System Termination

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-64694

The vulnerability affects local operating system components on macOS. These components are not designed to be directly exposed to the public internet, and system termination issues in this context typically require local execution or user interaction, making internet-facing reachability very unlikely.

Integer Overflow

Apple Macos

14.0 to before 14.8.815.0 to before 15.7.826.0 to before 26.6

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This advisory details a critical vulnerability found in Apple's macOS operating system that could allow an application to cause unexpected system shutdowns. The issue stems from an integer overflow, which has been addressed through improved input validation in recent updates. While the direct exposure to the public internet is unlikely, the severity of the flaw warrants attention to confirm its relevance and exposure within our environment.

Unexpected system shutdowns possible in macOS.
Critical flaw impacts core system stability.
Confirm relevance and potential exposure.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by sending specially crafted data to an affected system. This could potentially lead to an application crashing, causing unexpected system termination.

No special access required.
Input validation flaw triggers vulnerability.
Unexpected system termination.

Live Threat

Current exploitation, exposure, and threat context

An integer overflow vulnerability in macOS could lead to unexpected system termination when an app is able to cause such an event. This may occur when the system handles malformed input, potentially impacting system stability.

System stability.
Malformed input processing.
Unexpected system termination.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in macOS impacts system stability, potentially leading to unexpected termination. Ownership typically falls to the device owner or IT infrastructure teams responsible for endpoint management. The initial action involves identifying all affected macOS systems, assessing their business criticality and exposure, and then coordinating with Apple's support or consulting vendor guidance for applying the necessary security updates.

Endpoint owners should manage remediation.
Verify system criticality and exposure.
Plan and apply security updates.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the macOS software affected by CVE-2026-64694?

This CVE impacts core components within Apple's macOS operating system, specifically Sequoia (version 15.7.8), Sonoma (version 14.8.8), and Tahoe (version 26.6). These operating systems serve as the foundational platform for Apple computers, managing hardware resources and enabling users to run various applications. The vulnerability exists within internal system processes responsible for handling data input.

How does an integer overflow cause system termination?

An integer overflow occurs when a program tries to store a number too large for its assigned memory space, causing the value to wrap around to an incorrect, often smaller number. In the context of CVE-2026-64694, this calculation error in input handling can confuse the system's logic. Because the system cannot process this unexpected value safely, it encounters a fatal error, which leads to the entire operating system terminating unexpectedly.

Do I need malicious network traffic to trigger this vulnerability?

Not necessarily. While the vulnerability involves processing crafted data, the trigger requires the system to receive specific, malformed input that exploits the integer overflow. Simply having a network connection does not trigger the bug; the system must be actively engaged in processing the problematic data. Standard, legitimate network traffic or typical user operations will not cause this termination issue.

Is my macOS device at risk from the internet?

According to Halo Surface Signal, this vulnerability is very unlikely to be reachable from the public internet. Because the affected components are internal operating system functions rather than services designed to listen for web traffic, an attacker cannot easily reach them remotely. The risk is significantly lower than for internet-facing applications, as the flaw generally requires local execution or interaction to manifest.

How should I respond to CVE-2026-64694?

The most effective response is to update your macOS devices to the versions specified in the security advisory. Begin by identifying which computers in your environment are running Sequoia 15.7.7 or earlier, Sonoma 14.8.7 or earlier, or Tahoe 26.5 or earlier. Prioritize these systems for patching, as these updates contain the improved input validation necessary to prevent the integer overflow from occurring.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.