External risk intelligence

Apple UDP Socket Logic Flaw Affects Multiple Operating Systems.

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2025-43359

The vulnerability involves a UDP server socket that is intended to be bound to a local interface but may inadvertently bind to all interfaces. While this creates potential for network exposure, these products are primarily client-side operating systems and consumer devices, not typically deployed as internet-facing services or gateways. Public internet exposure is uncommon and generally occurs only under specific configurations.

Apple Ipados

before 18.714.0 to before 14.815.0 to before 15.7before 26.0

Halo Surface Signal: 2 out of 5 — less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A logic issue was found in Apple operating systems that could allow a server socket, intended for local use, to become accessible on all network interfaces. This could lead to broader network exposure than anticipated. The main concern is confirming relevance and exposure.

A logic flaw could expose local network services.
Understand the risk of unintended network exposure.
Confirm if this impacts any of your Apple devices.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this issue by sending crafted network traffic to a device. This could cause a UDP server socket, which should only listen for local connections, to instead listen on all network interfaces, potentially exposing sensitive services to the network.

Network access required.
Triggers by sending network packets.
Can lead to broad network exposure.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow a network-accessible UDP server socket, intended to be confined to a local interface, to become accessible from all network interfaces. This condition could potentially expose services that rely on this socket to unauthorized network traffic.

Local UDP server socket.
Socket may bind to all interfaces.
Unauthorized network access to services.

Operational Fix

Recommended remediation, mitigation, and detection steps

Determine the scope of affected Apple devices within your environment and assess their network exposure. Confirm ownership of these devices and prioritize remediation based on business criticality and risk.

Confirm device ownership and network exposure.
Prioritize remediation based on criticality.
Plan and execute updates in 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.

Free EASM Trial See How Signal Works

Frequently asked questions

What is the software affected by CVE-2025-43359?

This CVE affects the core networking components within Apple's operating system family, including iOS, iPadOS, macOS, tvOS, visionOS, and watchOS. These systems use internal software services to manage communication between devices and applications. When these services handle networking sockets incorrectly, they can unintentionally change how the device interacts with the network.

How should I understand the vulnerability CVE-2025-43359?

This is a logic error classified as CWE-670 (Always-Incorrect Control Flow Implementation). In simple terms, the system makes a mistake in managing network connection rules. It fails to restrict a UDP socket to a private, local interface, causing the system to mistakenly open that connection to all available network interfaces instead.

What triggers the socket binding issue in this CVE?

The flaw is triggered when the operating system processes network traffic that interacts with these specific UDP server sockets. It is important to note that simply having an Apple device does not trigger this; the condition arises from the internal logic error during socket initialization. The bug does not trigger for services correctly configured to ignore external broadcast requests.

Is my device at risk based on Halo Surface Signal?

Halo Surface Signal labels the risk as unlikely for most users. Because these products are client-side operating systems rather than internet-facing servers or network gateways, they are not typically exposed to the public internet. Most devices will not face this risk unless they are running specific, uncommon configurations that allow broader network access.

Do I need to update my Apple devices for this?

Yes, you should apply the latest available updates for your operating system. Since this is a logic flaw within the system software, updating to the versions specified in the advisory is the standard way to resolve the incorrect socket behavior. Prioritize updates on devices that perform specialized network functions or handle sensitive services.

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.