External risk intelligence

Apple Use After Free Vulnerability Allows Kernel Memory Corruption

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-43778

The vulnerability affects client-side operating systems (iOS, iPadOS, macOS, tvOS, visionOS, and watchOS) and requires an app to be running on the device to trigger the issue. These are end-user devices, not network-facing services, gateways, or internet-accessible servers.

Use After Free

Apple Ipados

before 26.614.0 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

A critical vulnerability has been identified in Apple's operating systems that could allow an application to terminate the system unexpectedly or corrupt memory. This issue is addressed in recent updates for iOS, iPadOS, macOS, tvOS, visionOS, and watchOS. The primary concern is confirming whether our environment and relevant devices have been updated to mitigate this risk.

Memory corruption flaw in operating systems.
Potential system termination or memory corruption.
Confirm system updates for affected devices.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by tricking a user into installing a malicious app. This app could then interact with the system in a way that triggers a use-after-free error, potentially leading to system termination or memory corruption.

Malicious app must be installed.
Vulnerable app component is triggered.
Risk of system termination or memory corruption.

Live Threat

Current exploitation, exposure, and threat context

When supported by the advisory, an app could trigger unexpected system termination or corrupt kernel memory. This means that a malicious app could potentially cause the device to crash or lead to instability by exploiting this vulnerability. The advisory does not indicate risks to specific system data, user data, or PII.

System instability or termination.
Malicious app execution.
Unexpected system behavior.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability affects Apple's client operating systems. System owners and their respective platform or infrastructure teams are likely responsible for remediation. The immediate first step is to inventory all affected Apple devices, confirm their reachability and business criticality, and then plan remediation activities.

Identify affected Apple devices and owners.
Verify device reachability and business criticality.
Plan remediation during approved maintenance windows.

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 software affected by CVE-2026-43778?

This vulnerability impacts Apple's ecosystem, specifically iOS, iPadOS, macOS (Sequoia, Sonoma, and Tahoe), tvOS, visionOS, and watchOS. These platforms serve as the core operating environments for Apple's mobile, desktop, streaming, spatial computing, and wearable hardware, managing fundamental system resources and application execution.

What does use-after-free mean in this vulnerability?

This is a memory management weakness, classified as CWE-416. It occurs when a program continues to use a pointer to a memory location after that memory has been cleared or released. In the context of CVE-2026-43778, this flaw allows a malicious application to manipulate the operating system's kernel memory, potentially causing system crashes or unauthorized memory modification.

How is this vulnerability triggered?

The issue is triggered by the execution of a malicious application on an affected device. The vulnerability does not require remote network interaction from an external actor to initiate; instead, it relies on the app interacting with the system's memory management processes. Simply visiting a website or browsing the internet without installing or running a specific app does not trigger this flaw.

Why should I care about this vulnerability?

According to Halo Surface Signal, this vulnerability is classified as 'Very unlikely' for most environments because it affects client-side end-user devices rather than network-facing servers or gateways. It requires an application to be locally active on the device. Owners should focus on devices that run third-party software, as these pose a higher risk of executing the malicious code required to trigger the error.

What should I do to address CVE-2026-43778?

The primary response is to update your Apple devices to the versions that include the memory management improvements, such as iOS 26.6, macOS 15.7.8, or their equivalent updates for other platforms. Start by creating an inventory of your organization's Apple hardware to ensure all affected devices are identified, then schedule the installation of these security updates during your next maintenance window.

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.