External risk intelligence

macOS Memory Corruption Vulnerability Allows Kernel Memory Write

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-43694

This vulnerability affects macOS system memory handling. It requires an app to be installed and running on a local device to trigger the issue, making it a client-side concern. It is not an internet-facing service, gateway, or network-accessible portal, and lacks typical public network exposure.

Memory Corruption

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 critical vulnerability affects macOS system memory handling, potentially allowing an application to crash the system or access sensitive kernel memory. While an app must be running locally to exploit this, the severity of potential data access and system disruption warrants attention. The primary concern is to confirm if any affected systems are running these specific macOS versions.

An app could crash the system or read protected memory.
Considered critical due to potential data access and disruption.
Confirm if macOS versions are relevant to your environment.

Attack Path

How an attacker could exploit the issue

An attacker could leverage this vulnerability if a malicious application is installed on a targeted macOS system. When this application is run, it can interact with the system in a way that triggers the memory handling flaw. This interaction can lead to an unexpected system termination or allow the application to write to kernel memory, potentially compromising the entire system's integrity.

An app must be installed and running.
Triggered by the vulnerable app's actions.
Risk of system termination or memory corruption.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow an application to unexpectedly terminate the system or write to kernel memory. This could occur when an app is running on a supported version of macOS.

System data could be affected.
An app could cause unexpected termination or memory writes.
System instability or data corruption may occur.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability impacts macOS system memory handling, requiring a local application to trigger the issue. Ownership likely falls to teams managing macOS endpoints, such as IT Operations or Endpoint Management, with initial steps focused on identifying affected devices and confirming business criticality. Coordination with the vendor for remediation planning is essential.

Endpoint management teams should own the issue.
Verify local macOS device exposure and criticality.
Plan coordinated remediation and vendor engagement.

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.

Free EASM Trial See How Signal Works

Frequently asked questions

What is macOS Sequoia, Sonoma, and Tahoe?

These are versions of the macOS operating system. macOS provides the core environment that manages computer hardware and allows applications to run. The kernel is the deepest part of this system, responsible for controlling memory, processor tasks, and how software interacts with hardware components.

What does CVE-2026-43694 mean by memory corruption?

This CVE involves a weakness categorized as CWE-119, where the system fails to properly manage memory boundaries. In plain terms, the software acts like a filing system that accidentally lets someone write documents into the wrong folders or access restricted areas they should not see. Because this flaw involves the kernel, it allows an application to bypass standard security protections and potentially alter critical system data or force the entire computer to shut down.

How is this vulnerability triggered?

To trigger the flaw, a malicious application must be successfully installed and executed on the device. Simply browsing the web or receiving a file does not trigger the vulnerability. The issue occurs when the application actively interacts with the system in a way that exploits the flawed memory handling logic. If the application is not running on the device, the system remains safe from this specific memory error.

Is my device at risk based on Halo Surface Signal?

Halo Surface Signal identifies this as a client-side issue, meaning it is not an internet-facing service or network portal. Because it requires a locally installed application to execute, it lacks the typical exposure profile of a server-side vulnerability. Your primary risk involves local users or processes accidentally running untrusted software rather than external attackers reaching your system directly over the public internet.

Do I need to update my macOS devices?

Yes, updating is the standard way to resolve this issue. First, check your system settings to identify if your devices are running macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, or macOS Tahoe 26.6. These versions contain the necessary improvements to how the system handles memory. Coordinate with your IT or endpoint management team to prioritize devices that handle sensitive information and plan for a phased update rollout to ensure all systems are patched.

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.