CVE-2026-43705: Apple Safari Use After Free Vulnerability

CVE-2026-43705 Overview

CVE-2026-43705 is a type confusion vulnerability [CWE-843] affecting Apple Safari, iOS, iPadOS, and macOS. Processing maliciously crafted web content can trigger memory corruption in the browser engine. Apple addressed the issue with improved type checks in Safari 26.5.2, iOS 26.5.2, iPadOS 26.5.2, and macOS Tahoe 26.5.2.

An attacker can exploit the flaw by luring a victim to a malicious webpage. Successful exploitation may lead to arbitrary code execution within the browser process context. The vulnerability affects confidentiality, integrity, and availability at a high level.

Critical Impact
Remote attackers can achieve memory corruption and potential code execution by convincing a user to open crafted web content in a vulnerable Apple browser or system component.

Affected Products

Apple Safari (prior to 26.5.2)
Apple iOS and iPadOS (prior to 26.5.2)
Apple macOS Tahoe (prior to 26.5.2)

Discovery Timeline

2026-06-29 - CVE-2026-43705 published to NVD
2026-06-30 - Last updated in NVD database

Technical Details for CVE-2026-43705

Vulnerability Analysis

The issue is a type confusion condition in Apple's web content processing stack, tracked under [CWE-843]. Type confusion occurs when code operates on an object assuming one type while the object is actually a different type. The mismatch enables out-of-bounds memory access and corruption of adjacent structures.

Because the flaw resides in the browser rendering pipeline, any Apple platform relying on the shared WebKit engine inherits the exposure. Attackers can chain the memory corruption primitive into control-flow hijacking under favorable heap conditions. The advisories from Apple confirm remediation through improved type validation checks.

Root Cause

The root cause is missing or insufficient type validation before an object is dereferenced or cast during web content processing. When JavaScript or Document Object Model (DOM) operations manipulate objects with unexpected type transitions, the engine performs unsafe operations on memory laid out for a different type. This produces predictable memory corruption an attacker can shape.

Attack Vector

The attack vector is network-based and requires user interaction. A victim must load attacker-controlled web content — through a malicious website, an ad iframe, or an embedded WebView. No privileges are required on the target device. Once the page loads, the crafted JavaScript triggers the type confusion and initiates the memory corruption primitive.

The vulnerability manifests during script execution against WebKit's object model. Refer to the Apple Support Document #127594, Apple Support Document #127595, and Apple Support Document #127685 for authoritative technical remediation details.

Detection Methods for CVE-2026-43705

Indicators of Compromise

Unexpected Safari or WebContent process crashes correlated with recent browsing activity.
Creation of unsigned or unusual child processes spawned by Safari or a WebKit-based application.
Outbound connections from com.apple.WebKit.WebContent to unfamiliar domains immediately after page load.
Sandbox violation entries in system.log referencing WebKit renderer processes.

Detection Strategies

Monitor endpoint telemetry for WebContent process crashes with heap corruption signatures such as EXC_BAD_ACCESS or KERN_INVALID_ADDRESS.
Inspect web proxy logs for user visits to newly registered or low-reputation domains preceding browser instability.
Correlate crash reports on managed macOS and iOS devices against known Safari versions below 26.5.2.

Monitoring Recommendations

Enforce inventory scans to identify Apple endpoints running Safari, iOS, iPadOS, or macOS builds below 26.5.2.
Track DNS and TLS SNI telemetry for connections to malvertising infrastructure that commonly stages browser exploits.
Alert on post-exploitation behaviors such as unexpected persistence writes under ~/Library/LaunchAgents following browser activity.

How to Mitigate CVE-2026-43705

Immediate Actions Required

Update Safari to version 26.5.2 on all macOS endpoints.
Update iOS and iPadOS devices to 26.5.2 through Mobile Device Management (MDM) or user prompts.
Update macOS to Tahoe 26.5.2 to remediate system-level WebKit components used by embedded WebViews.
Restrict browsing to trusted destinations on unpatched devices until updates complete.

Patch Information

Apple released fixes in Safari 26.5.2, iOS 26.5.2, iPadOS 26.5.2, and macOS Tahoe 26.5.2. The fixes introduce improved type checks in the affected code paths. Detailed remediation is documented in the Apple Support Document #127594, Apple Support Document #127595, and Apple Support Document #127685.

Workarounds

Disable JavaScript in Safari for high-risk users until patches are deployed, accepting reduced site functionality.
Route managed device traffic through a filtering proxy that blocks known malicious and newly registered domains.
Use MDM configuration profiles to enforce Safari content restrictions on iOS and iPadOS fleets.

bash

# Verify Safari version on macOS
mdls -name kMDItemVersion /Applications/Safari.app

# Trigger software update check on macOS
sudo softwareupdate --list
sudo softwareupdate --install --all --restart