External risk intelligence

Race Condition in Apple Operating Systems Allows Unexpected System Termination

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-64720

This vulnerability affects client-side operating systems (iOS, iPadOS, macOS, tvOS, watchOS). The vulnerability requires an app to be present on the device to trigger the issue, making it a client-side execution scenario rather than a public-facing network service or internet-exposed infrastructure.

Apple Ipados

before 26.626.0 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 addresses a critical vulnerability in Apple's operating systems that could allow an application to unexpectedly terminate the system. While the exploit requires an app to be present, the high severity indicates a potential for significant disruption. The primary concern is to confirm if our environment has exposure to this issue.

Apps may cause unexpected system shutdowns.
Critical flaw impacts multiple Apple platforms.
Confirm relevance and potential exposure.

Attack Path

How an attacker could exploit the issue

An attacker could leverage a race condition in the operating system, allowing a malicious application to trigger unexpected system termination. This vulnerability, fixed in recent versions of Apple's operating systems, could be exploited by any application installed on the device.

App installed on device
Race condition in system handling
Unexpected system termination

Live Threat

Current exploitation, exposure, and threat context

A race condition could lead to an app causing unexpected system termination. This could affect system stability and availability when supported by the advisory.

System stability and availability.
An app could trigger unexpected termination.
Users may experience service disruption.

Operational Fix

Recommended remediation, mitigation, and detection steps

This critical vulnerability impacts Apple's client-side operating systems and requires an app to be present on the device for exploitation, suggesting a focus on endpoint security teams and device owners. The immediate first step is to inventory all devices running the affected operating systems, confirm their network reachability and business criticality, identify the accountable owner for each device or user group, and then prioritize remediation efforts based on this risk assessment.

Identify device owners and operating systems.
Verify device reachability and criticality.
Plan risk-based remediation actions.

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 iOS, iPadOS, macOS, tvOS, and watchOS?

These are Apple's core operating systems powering devices like iPhones, iPads, Macs, Apple TV, and Apple Watch. They provide the foundational software layer that manages hardware resources and runs user applications. This CVE specifically addresses an issue within the system-level state management of these platforms, ensuring that these different devices maintain stability when apps interact with system processes.

What does CVE-2026-64720 mean by a race condition?

This vulnerability is classified as CWE-362, which refers to a race condition. In technical terms, it happens when a system's output depends on the timing or sequence of uncontrollable events. In this instance, the operating system fails to handle the state of certain operations correctly, allowing a malicious application to trigger an error that forces the entire system to shut down unexpectedly.

Do I need to be logged into a specific app to trigger this?

The vulnerability requires a malicious app to be installed and active on the device to initiate the race condition. It is not triggered by simply browsing the web or receiving a network packet alone. The bug requires local execution; if there is no malicious software present to exploit the specific system state, the condition cannot be triggered.

How relevant is this CVE to my infrastructure?

According to Halo Surface Signal, this is unlikely to be an immediate network-based risk. Because it affects client-side operating systems and requires an app to be present on the device, it is categorized as a client-side execution scenario rather than a public-facing network service. The risk is primarily tied to endpoints managed by your organization rather than internet-exposed servers.

How should I respond to this Apple vulnerability?

Your first step is to verify which devices in your environment are running affected versions of Apple's operating systems. Since the fix is included in version 26.6 across these platforms, you should prioritize updating those devices to this version. Focus your efforts on identifying managed devices, confirming their current OS version, and scheduling updates to ensure system stability.

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.