External risk intelligence

macOS Out-of-Bounds Read Allows Unexpected System Termination

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-43757

This vulnerability affects macOS system components. The issue requires the execution of an application on a local system to cause unexpected termination. It does not represent a service or interface that is exposed to the public internet for remote connectivity or management.

Out-of-bounds Read

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

An out-of-bounds read vulnerability has been identified in macOS system components, which could potentially lead to unexpected system termination. While the issue is fixed in recent updates, the primary concern for leadership is to confirm if this specific technology is in use within the organization and assess any potential exposure.

An issue could cause unexpected system termination.
Matters if macOS is in use.
Confirm relevance and exposure.

Attack Path

How an attacker could exploit the issue

An attacker could potentially trigger this vulnerability through a network-accessible application that is capable of interacting with a vulnerable macOS system component. This interaction could lead to an out-of-bounds read, potentially resulting in unexpected system termination.

Network access required.
Triggered by application interaction.
Risk of unexpected system termination.

Live Threat

Current exploitation, exposure, and threat context

An out-of-bounds read could lead to an application causing unexpected system termination when supported by the advisory. This vulnerability does not appear to pose a risk to system data, user data, or sensitive information.

System stability may be impacted.
An app could trigger unexpected termination.
Service availability could be disrupted.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability affects macOS system components, meaning teams responsible for endpoint management and device security, such as IT infrastructure or desktop support, are likely responsible for remediation. The first practical step is to identify all macOS devices within the environment, confirm their operating system versions, and assess the business criticality of any affected systems before planning a phased rollout of updates during a maintenance window.

Endpoint management teams own remediation.
Verify macOS devices and OS versions.
Plan and deploy OS 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-2026-43757?

This vulnerability impacts core macOS system components across several versions, including macOS Sequoia, Sonoma, and Tahoe. These components perform essential background tasks and manage low-level operations; they are standard parts of the operating system that enable your computer to run applications and interface with hardware.

What does an out-of-bounds read vulnerability mean?

In CVE-2026-43757, this weakness (CWE-125) occurs when software reads data past the end of a designated memory buffer. Think of it like reading beyond the edge of a page; instead of stopping, the system attempts to access memory it shouldn't. In this specific case, the process fails to handle that invalid request gracefully, leading to an unexpected system termination.

How is this vulnerability triggered?

An attacker must execute a specific application that interacts with the vulnerable macOS component to trigger the error. It is important to note that simply browsing the web or receiving data is not enough; the bug requires an active, malicious application running locally to successfully force the system to read out-of-bounds and crash.

Do I need to worry about this from the internet?

According to Halo Surface Signal, this is considered very unlikely to be an external threat. Because this issue resides in local macOS system components, it is not a public-facing service or internet-accessible interface. The risk is limited to local application interaction rather than remote exploitation over the network.

How should I respond to CVE-2026-43757?

The most effective response is to update your systems to the patched versions: macOS Sequoia 15.7.8, Sonoma 14.8.8, or Tahoe 26.6. Begin by identifying all macOS devices in your inventory, verifying their current OS build, and scheduling the installation of these updates during your standard maintenance window to restore 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.