External risk intelligence

Apple WebKit Memory Handling Vulnerability Affects Safari and Operating Systems.

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2025-43343

The vulnerability affects web browsers (Safari) and WebKit-based engines, which are designed to process untrusted web content from the public internet. Because web browsers are standard tools for navigating public internet resources and are explicitly designed to render external content, the exposure surface is high.

Memory Corruption

Apple Safari

before 26.0before 2.50.1

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This critical vulnerability affects web content processing across multiple Apple operating systems and WebKit. The issue could lead to unexpected process crashes, potentially impacting system stability. The main concern is confirming relevance and exposure within your environment.

Malicious web content can crash systems.
Affects core browsing and operating system functions.
Confirm relevance and assess potential exposure.

Attack Path

How an attacker could exploit the issue

An attacker could lead a victim to a specially crafted website, causing the browser to crash unexpectedly. This could occur over the network without requiring any special privileges.

No privileges needed to initiate.
Victim visits malicious website.
Unexpected process crash.

Live Threat

Current exploitation, exposure, and threat context

When supported by the advisory, processing maliciously crafted web content could lead to an unexpected crash in Safari and other WebKit-based browsers. This vulnerability does not appear to put specific types of system data, user data, or PII at direct risk beyond the immediate impact of a crash.

Browser process may crash.
Malicious web content could trigger the crash.
Service disruption may occur.

Operational Fix

Recommended remediation, mitigation, and detection steps

This critical vulnerability impacting Apple's Safari, iOS, iPadOS, macOS, tvOS, visionOS, and watchOS, as well as WebKitGTK and WPE WebKit, requires immediate attention from teams managing these platforms. The first practical step is to identify all instances of the affected software, confirm their exposure and business criticality, and then assign an accountable owner to plan and execute remediation.

Identify and assign platform owners.
Verify external reachability and criticality.
Plan and coordinate timely remediation.

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-2025-43343?

This vulnerability impacts the WebKit rendering engine, which powers the Safari browser and Apple operating systems like iOS, macOS, visionOS, and watchOS. It also affects WebKitGTK and WPE WebKit, which are frequently used by Linux-based applications to display web content. These components are essential tools that allow devices to fetch, interpret, and display data from the internet.

What does CWE-119 mean in the context of this vulnerability?

CWE-119 is a weakness class involving improper memory handling. In CVE-2025-43343, this means the software does not correctly manage the memory it uses when processing complex web data. This oversight allows an attacker to provide maliciously crafted content that overwhelms or confuses the browser's memory management, forcing the process to terminate unexpectedly.

How does an attacker trigger this vulnerability?

An attacker triggers this issue by tricking a user into visiting a website containing specially crafted content. The process is not triggered by simply having the software installed or by routine network traffic; it specifically requires the browser or engine to parse and render the malicious web content. Normal, benign web browsing does not cause this crash.

Is my system at risk if it uses this software?

According to Halo Surface Signal, this vulnerability is highly relevant because browsers are explicitly designed to process untrusted content from the public internet. Since these applications must interact with the web to function, any device running an unpatched version is considered exposed to potential service disruption if a user navigates to a malicious page.

How should I respond to this threat?

Begin by identifying all systems and devices in your environment that utilize the affected Safari or WebKit versions. Once identified, prioritize these for updates to the version 26 series or higher, which includes the necessary memory handling improvements. Assign responsibility to the appropriate technical leads to track and verify that these updates are successfully applied.

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.