External risk intelligence

Apple Use After Free Vulnerability Affects Multiple Operating Systems

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-43799

This vulnerability affects client-side operating systems and software (iOS, iPadOS, macOS, tvOS, visionOS, watchOS). These products are typically used as end-user devices rather than public-facing servers or internet-exposed services. The vulnerability is triggered by an application, which does not constitute a public-facing network service or internet-reachable attack surface.

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

This vulnerability involves a memory management issue in Apple's operating systems, which could potentially lead to unexpected system termination when an app is used. While the primary impact is system instability, the broad applicability across multiple Apple devices warrants awareness. The main concern is confirming relevance and exposure.

An app could crash the system unexpectedly.
Affects widely used Apple operating systems.
Understand relevance; consider system stability.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by sending a specially crafted message to a vulnerable device over the network, which could then lead to an application crashing or the system unexpectedly terminating. This could potentially allow an attacker to access sensitive information or disrupt device functionality.

No special access required.
Triggered by application interaction.
Potential for system termination.

Live Threat

Current exploitation, exposure, and threat context

A use-after-free vulnerability could allow a malicious application to crash the system. This could occur when an app triggers the flawed memory management.

System stability and availability.
Triggered by a malicious app.
Unexpected system termination.

Operational Fix

Recommended remediation, mitigation, and detection steps

The teams most likely responsible for addressing this vulnerability are those managing Apple endpoints, including endpoint engineering, IT operations, and security operations. The initial step should be to identify all devices running the affected operating systems, assess their exposure and criticality, and then coordinate with device owners or asset management to plan for updates during planned maintenance windows.

Device owners should prioritize affected systems.
Verify operating system versions and device reachability.
Plan for coordinated updates and patching.

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 the software affected by CVE-2026-43799?

This vulnerability affects a broad range of Apple operating systems, including iOS, iPadOS, several versions of macOS (Sequoia, Sonoma, Tahoe), as well as tvOS, visionOS, and watchOS. These platforms serve as the foundation for the hardware ecosystem used by millions, powering everything from mobile devices and wearables to desktop and home computing equipment.

What is a use-after-free vulnerability?

A use-after-free, classified as CWE-416, is a memory management flaw. It occurs when a program continues to use a memory address after that memory has been cleared or assigned to something else. Because the program is interacting with undefined data, it can lead to instability, such as an unexpected system termination, as the application or OS struggles to process the invalid memory state.

How is this vulnerability triggered?

The issue is triggered by an application interacting with the operating system's flawed memory management process. A specially crafted input or interaction from a malicious app can cause the system to crash. Importantly, this bug is not triggered by normal, benign usage or routine background tasks; it requires the specific, abnormal interaction that hits the corrupted memory state.

Is my device at high risk according to Halo Surface Signal?

Halo Surface Signal identifies this as very unlikely to be an internet-exposed threat. Because the vulnerability resides in client-side operating systems—rather than public-facing servers—it does not inherently present a standard network attack surface. The primary risk is limited to malicious applications already interacting with the device, rather than remote network exploitation.

Do I need to update my Apple devices?

Yes. To resolve this memory management issue, you should update your devices to version 26.6 for iOS, iPadOS, macOS Tahoe, tvOS, visionOS, and watchOS, or to version 15.7.8 for macOS Sequoia and 14.8.8 for macOS Sonoma. Start by auditing your inventory to locate devices on older versions, then coordinate updates through your standard maintenance cycles to restore proper memory handling.

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.