External risk intelligence

macOS Integer Overflow Leads to Unexpected System Termination

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-43764

This vulnerability affects local macOS system components and applications. Such software is intended for client-side use on individual devices rather than functioning as an internet-facing service, gateway, or public-facing network infrastructure.

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 CVE describes an integer overflow vulnerability in macOS that could allow an application to cause unexpected system termination. The issue has been addressed with improved input validation. The main concern is confirming relevance and exposure within our environment.

An app may crash the system.
It impacts common user devices.
Confirm if our macOS devices are affected.

Attack Path

How an attacker could exploit the issue

An attacker could remotely send specially crafted data to a vulnerable macOS system, triggering an integer overflow. This overflow can then lead to an unexpected system termination.

Requires no prior access or privileges.
Triggered by sending malformed data.
Results in 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 application performs specific operations. This could impact the stability and availability of the affected system.

System stability and availability.
Malicious app causes unexpected termination.
System instability, denial of service.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability impacts macOS systems, suggesting that teams responsible for endpoint management, client application deployment, and overall OS security are likely to be involved. The first practical step is to identify all macOS devices within the environment, determine their business criticality and network exposure, and confirm the responsible owner for each asset before planning remediation.

Endpoint and OS teams own the issue.
Verify macOS device exposure and criticality.
Plan phased remediation based on risk.

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 macOS Sequoia, Sonoma, and Tahoe?

These are versions of the Apple macOS operating system, which serves as the core software platform for Mac computers. They manage system resources, run user applications, and handle background processes. This vulnerability specifically affects the underlying system code within these releases, meaning the flaw exists at the platform level rather than in a third-party application.

What does integer overflow mean for CVE-2026-43764?

An integer overflow (CWE-190) occurs when a program tries to store a number that is too large for the memory space allocated to it. In this case, the system's math calculation 'wraps around' to a different value. Because the software does not correctly handle this unexpected result, it triggers an error that forces the operating system to shut down abruptly.

How is this vulnerability triggered?

An attacker triggers this issue by sending specially crafted, malformed data to a vulnerable macOS system. It is important to note that simply running standard, legitimate applications or performing typical daily tasks on your Mac does not trigger this flaw. The crash requires specific, malicious input designed to exploit the lack of input validation in the affected system component.

Is my Mac at risk according to Halo Surface Signal?

Halo Surface Signal notes that this vulnerability affects local macOS system components, which are typically used on individual devices rather than acting as internet-facing network infrastructure like servers or gateways. While the bug is technically reachable over a network, its primary impact is on client-side devices, making it less likely to be a target for mass automated attacks compared to server software.

Do I need to update my macOS devices?

Yes. Since this issue can cause unexpected system termination, the first step is to identify all macOS devices in your fleet and verify their current OS version. Ensure those running macOS Sequoia 15.7.8, Sonoma 14.8.8, or Tahoe 26.6 are deployed, as these updates contain the improved input validation necessary to prevent this vulnerability from being triggered.

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.