CVE-2025-43432: Apple Safari Use-After-Free Vulnerability

CVE-2025-43432 Overview

CVE-2025-43432 is a use-after-free vulnerability [CWE-416] affecting Apple's web content processing across Safari, iOS, iPadOS, macOS, tvOS, visionOS, and watchOS. Processing maliciously crafted web content may lead to an unexpected process crash. Apple addressed the flaw through improved memory management in Safari 26.1 and the corresponding 26.1 releases of its operating systems. The vulnerability requires user interaction, such as visiting a hostile web page, and network-based delivery. While the impact is limited to availability, use-after-free conditions in browser engines historically warrant prompt patching due to their potential as building blocks in exploit chains.

Critical Impact
Remote attackers can trigger an unexpected process crash on Apple devices by luring users to maliciously crafted web content, affecting availability across Safari and Apple operating systems.

Affected Products

Apple Safari (versions prior to 26.1)
Apple iOS and iPadOS (versions prior to 26.1)
Apple macOS Tahoe, tvOS, visionOS, and watchOS (versions prior to 26.1)

Discovery Timeline

2025-11-04 - CVE-2025-43432 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-43432

Vulnerability Analysis

The vulnerability is a use-after-free condition [CWE-416] in the web content processing pipeline used by Safari and Apple platform WebKit components. A use-after-free occurs when a program continues to reference memory after that memory has been freed, allowing subsequent operations to act on invalid or reallocated data. In browser engines, such flaws often arise from complex object lifetimes during Document Object Model (DOM) manipulation, JavaScript garbage collection, or asynchronous rendering events. Apple states the issue was addressed with improved memory management. Exploitation results in an unexpected process crash, indicating loss of availability for the affected web content process.

Root Cause

The defect stems from improper tracking of object lifetimes within Apple's web content rendering. When an object is freed but a dangling reference persists, later access to that reference causes the process to operate on invalid memory. Apple's fix in the 26.1 releases hardens allocation and reference handling to eliminate the dangling access path.

Attack Vector

Exploitation requires a user to load attacker-controlled web content in Safari or in an application that uses the affected WebKit component. No privileges are required, and the attack originates over the network. The observed impact is a crash of the affected process, denying service to the browsing session. Attackers frequently pair use-after-free primitives with additional flaws to escalate impact, so defenders should not treat crash-only reports as inherently benign.

No public proof-of-concept or exploit code has been released for CVE-2025-43432 at the time of publication. Refer to the Apple Security Advisory #125634 for vendor technical details.

Detection Methods for CVE-2025-43432

Indicators of Compromise

Repeated unexpected crashes of Safari or WebKit-based application processes on Apple endpoints, particularly com.apple.WebKit.WebContent.
Crash reports in ~/Library/Logs/DiagnosticReports/ referencing WebKit frames and memory access violations.
Outbound network connections from managed browsers to newly registered or low-reputation domains preceding crash events.

Detection Strategies

Monitor endpoint telemetry for abnormal termination of WebKit content processes correlated with recent URL navigations.
Correlate browser crash events with web proxy or DNS logs to identify malicious content URLs.
Track OS and Safari version inventory to identify hosts running vulnerable builds prior to the 26.1 release train.

Monitoring Recommendations

Ingest macOS unified logs and DiagnosticReports into a centralized logging or SIEM platform for browser crash analytics.
Alert on clusters of WebKit process crashes across multiple users, which may indicate targeted or drive-by content.
Maintain patch-state dashboards covering Safari, iOS, iPadOS, macOS, tvOS, visionOS, and watchOS to confirm remediation coverage.

How to Mitigate CVE-2025-43432

Immediate Actions Required

Update to Safari 26.1, iOS 26.1, iPadOS 26.1, macOS Tahoe 26.1, tvOS 26.1, visionOS 26.1, and watchOS 26.1 across all managed Apple devices.
Enforce patch compliance through mobile device management (MDM) policies and block non-compliant devices from sensitive resources.
Advise users to avoid opening untrusted links until patching completes.

Patch Information

Apple released fixes in the 26.1 update wave. Consult the vendor advisories: Apple Security Advisory #125632, Apple Security Advisory #125637, Apple Security Advisory #125638, Apple Security Advisory #125639, and Apple Security Advisory #125640 for platform-specific details.

Workarounds

Restrict browsing to trusted sites and enable content filtering at the network egress to reduce exposure to malicious pages.
Deploy web reputation and DNS filtering to block known malicious domains hosting exploit content.
Where feasible, use enterprise browser policies to disable risky features such as auto-loading of untrusted content until patches are applied.

bash

# Verify Safari version on macOS
defaults read /Applications/Safari.app/Contents/Info.plist CFBundleShortVersionString

# Trigger MDM-managed software update check
sudo softwareupdate --list
sudo softwareupdate --install --all --restart