CVE-2025-43212: Apple Safari DoS Vulnerability

CVE-2025-43212 Overview

CVE-2025-43212 is a memory handling flaw affecting Apple Safari and multiple Apple operating systems. Processing maliciously crafted web content can trigger an unexpected Safari crash, resulting in a denial-of-service condition on the target device. The vulnerability is categorized under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer). Apple addressed the issue with improved memory handling across its product ecosystem. The flaw affects Safari 18.6, iOS 18.6, iPadOS 18.6, macOS Sequoia 15.6, tvOS 18.6, visionOS 2.6, and watchOS 11.6. Exploitation requires user interaction, as a victim must load attacker-controlled web content.

Critical Impact
Processing maliciously crafted web content may lead to an unexpected Safari crash, causing availability loss on affected Apple devices.

Affected Products

Apple Safari (prior to 18.6)
Apple iOS and iPadOS (prior to 18.6), Apple macOS Sequoia (prior to 15.6)
Apple tvOS 18.6, visionOS 2.6, and watchOS 11.6

Discovery Timeline

2025-07-30 - CVE-2025-43212 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-43212

Vulnerability Analysis

The vulnerability resides in how Safari and its underlying WebKit-based rendering components handle memory when processing web content. When a user visits a page containing maliciously crafted markup, script, or media resources, the browser triggers improper memory operations that lead to an unexpected process crash. The flaw is classified as a memory buffer boundary violation under [CWE-119]. While the advisory does not describe code execution, the crash condition disrupts browsing sessions and can be weaponized for targeted denial of service. The issue impacts the shared WebKit code paths used across iOS, iPadOS, macOS, tvOS, visionOS, and watchOS, which is why Apple issued a coordinated fix across all major platforms.

Root Cause

The root cause is improper memory handling within Safari's web content processing routines. Apple's advisory states the issue was addressed with improved memory handling, indicating a boundary or lifetime error in how buffers were allocated, accessed, or released during content parsing.

Attack Vector

An attacker delivers a malicious webpage or hosted content that a victim opens in a vulnerable Safari or WebKit-based browser. The attack requires network access and user interaction, such as clicking a link or loading an embedded resource. Successful exploitation causes Safari to crash without persistent compromise of confidentiality or integrity.

// No verified public proof-of-concept code is available for CVE-2025-43212.
// See Apple advisories referenced below for vendor-supplied technical details.

Detection Methods for CVE-2025-43212

Indicators of Compromise

Repeated unexpected Safari or WebKit process crashes on iOS, iPadOS, or macOS devices when loading specific URLs.
Crash reports referencing WebKit memory faults in /Library/Logs/DiagnosticReports/ on macOS or Analytics logs on iOS.
User reports of browser instability tied to visits to untrusted websites or embedded WebView content.

Detection Strategies

Inventory endpoints by OS build and flag devices running Safari earlier than 18.6, iOS/iPadOS earlier than 18.6, macOS Sequoia earlier than 15.6, or watchOS/tvOS/visionOS below the patched builds.
Correlate abnormal Safari or WebKit process termination events with recent browsing activity to identify targeted delivery attempts.
Monitor web proxy and DNS telemetry for user visits to newly registered or low-reputation domains hosting suspicious HTML or JavaScript payloads.

Monitoring Recommendations

Ingest macOS unified logs and iOS device management crash telemetry into a centralized SIEM for correlation across users.
Alert on clusters of Safari crashes affecting multiple users, which may indicate a phishing or watering-hole campaign.
Track patch compliance for Safari and Apple OS builds through MDM reporting to close exposure gaps quickly.

How to Mitigate CVE-2025-43212

Immediate Actions Required

Update Safari to version 18.6 and upgrade Apple operating systems to the fixed builds: iOS 18.6, iPadOS 18.6, macOS Sequoia 15.6, tvOS 18.6, visionOS 2.6, and watchOS 11.6.
Push updates through mobile device management (MDM) profiles to enforce timely deployment across the fleet.
Educate users to avoid opening untrusted links, particularly from unsolicited messages, until patches are applied.

Patch Information

Apple released fixes in Safari 18.6, iOS 18.6, iPadOS 18.6, macOS Sequoia 15.6, tvOS 18.6, visionOS 2.6, and watchOS 11.6. Refer to the Apple Support Documentation for iOS 18.6 and iPadOS 18.6 and the Apple Support Documentation for macOS Sequoia 15.6 for full details on updated builds and additional CVEs resolved.

Workarounds

Restrict use of Safari on unpatched devices and route browsing through an alternative hardened browser where feasible.
Enforce web content filtering at the network edge to block known malicious or low-reputation domains.
Disable auto-loading of untrusted content and enable Lockdown Mode on high-risk Apple devices to reduce WebKit attack surface.

bash

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

# Trigger a software update check via command line
sudo softwareupdate --list
sudo softwareupdate --install --all --restart