External risk intelligence

macOS Logic Issue Allows Network Connection Interception

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-43779

The vulnerability involves an application intercepting network connections intended for another process on a macOS system. This is a local inter-process communication and local network stack issue, not a service or application designed to be exposed to or reachable from the public internet.

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

A logic issue in macOS could allow an application to intercept network connections intended for other processes. This could have significant implications for data confidentiality and integrity if exploited. The main concern is confirming relevance and exposure to our environment.

Apps may intercept network traffic.
Protects against unauthorized data interception.
Verify impact and ensure security posture.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by tricking a user into running a malicious application. This application could then intercept network traffic meant for other processes, potentially leading to the theft of sensitive information or the disruption of normal system operations. The vulnerability is fixed in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, and macOS Tahoe 26.6.

No authentication or user interaction needed.
Malicious app intercepts network connections.
Sensitive data theft or system disruption.

Live Threat

Current exploitation, exposure, and threat context

When supported by the advisory, an app may be able to intercept network connections intended for other processes on a macOS system.

System network connections.
App intercepts network traffic.
Unauthorized data access may occur.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in macOS affects network connection interception, making it critical for teams managing macOS endpoints. The first step is to identify all macOS systems, determine their exposure and business criticality, and assign ownership to the relevant endpoint or platform team.

Endpoint or Platform teams own the issue.
Verify affected macOS systems are inventoried.
Plan targeted updates or system isolation.

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. They act as the foundation for running all desktop applications, managing system resources, and handling network communications for users. This CVE impacts the core networking logic within these specific OS releases, which govern how different programs send and receive data across the system.

How does CVE-2026-43779 enable network interception?

This vulnerability falls under CWE-284, which concerns improper access control. It reflects a flaw in the system's internal logic that manages how network traffic is routed. Because the system fails to correctly restrict these paths, a malicious app can essentially step in and divert data packets meant for a legitimate process, allowing the attacker to see or modify information that should have remained private to the original app.

Do I need to be running a specific app to trigger this?

Yes, an attacker must first get a malicious application onto your system. It does not trigger via simple web browsing or visiting a site; the malicious code must be executed locally on the macOS device. If you only run trusted software from verified sources, you significantly reduce the risk, as the system remains secure when no unauthorized applications are present to exploit this logic path.

Is this vulnerability dangerous if I am not internet-facing?

According to Halo Surface Signal, this is primarily a local issue. Even if your machine is not exposed to the public internet, the threat remains if a user is tricked into running malicious software locally. Because the interception happens within the internal network stack of the operating system itself, the risk is centered on the integrity of the individual device rather than its connectivity to the outside world.

How do I fix CVE-2026-43779?

The primary response is to update your macOS devices to the versions where this logic issue was corrected: macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, or macOS Tahoe 26.6. Start by performing an inventory of all macOS assets in your environment to identify which machines are running older, vulnerable versions. Once identified, coordinate with your platform teams to schedule and deploy these updates to ensure the security of your systems.

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.