CVE-2025-43216 Overview
CVE-2025-43216 is a use-after-free vulnerability [CWE-416] 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. Apple addressed the issue with improved memory management in Safari 18.6, iOS 18.6, iPadOS 18.6, iPadOS 17.7.9, macOS Sequoia 15.6, tvOS 18.6, visionOS 2.6, and watchOS 11.6. The vulnerability requires user interaction, typically visiting an attacker-controlled webpage, and can be triggered over the network without authentication.
Critical Impact
Remote attackers can crash Safari by serving malicious web content to a target user, disrupting browser availability across iOS, macOS, iPadOS, tvOS, visionOS, and watchOS devices.
Affected Products
- Apple Safari (prior to 18.6)
- Apple iOS and iPadOS (prior to 18.6, and iPadOS 17.7.9)
- Apple macOS Sequoia (prior to 15.6), tvOS (prior to 18.6), visionOS (prior to 2.6), watchOS (prior to 11.6)
Discovery Timeline
- 2025-07-30 - CVE-2025-43216 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-43216
Vulnerability Analysis
The vulnerability is a use-after-free condition in Safari's web content processing pipeline. A use-after-free flaw occurs when a program continues to reference memory after it has been freed, allowing an attacker to influence the behavior of the freed region. In this case, processing specially crafted web content causes Safari to dereference a stale pointer, leading to an unexpected crash. The impact is limited to availability, with no confirmed impact on confidentiality or integrity.
Root Cause
The root cause is improper memory management in Safari's rendering engine when handling specific web content structures. An object is released while a reference to it remains reachable, and subsequent access to that freed object causes memory corruption. Apple's fix introduces improved memory lifetime tracking to prevent stale references from being used after deallocation.
Attack Vector
Exploitation requires an unauthenticated remote attacker to lure a victim into loading crafted web content in Safari or a WebKit-based application. The user must interact by navigating to the malicious page or opening a link that triggers WebKit rendering. Once the vulnerable code path executes, the process crashes. The vulnerability does not require elevated privileges but does require user interaction, and the scope remains unchanged.
No public proof-of-concept has been verified for this CVE. Technical discussion is available through the Full Disclosure July 2025 posts and the Openwall OSS-Security advisory.
Detection Methods for CVE-2025-43216
Indicators of Compromise
- Unexpected Safari or WebKit-based application crashes reported in ~/Library/Logs/DiagnosticReports/ on macOS or via CrashReporter on iOS.
- Repeated crash reports referencing WebKit or com.apple.WebKit.WebContent processes following navigation to a specific URL.
- Outbound connections from managed endpoints to newly registered or low-reputation domains preceding browser crashes.
Detection Strategies
- Monitor endpoint telemetry for abnormal termination signals from Safari and WebKit content processes across managed Apple devices.
- Correlate browser crash events with URL history and DNS logs to identify repeated navigation to suspicious hosts.
- Track Safari and OS build versions across the fleet to identify endpoints still running vulnerable versions.
Monitoring Recommendations
- Aggregate macOS and iOS crash telemetry into a centralized logging platform for trend analysis.
- Alert on clusters of WebKit crashes affecting multiple users navigating a common domain, which may indicate active exploitation attempts.
- Track patch compliance for Safari 18.6, iOS/iPadOS 18.6, iPadOS 17.7.9, macOS Sequoia 15.6, tvOS 18.6, visionOS 2.6, and watchOS 11.6.
How to Mitigate CVE-2025-43216
Immediate Actions Required
- Update Safari to 18.6 and upgrade Apple operating systems to the fixed versions listed in the Apple advisories.
- Enforce OS and browser update policies through mobile device management for iOS, iPadOS, tvOS, visionOS, and watchOS fleets.
- Educate users to avoid clicking untrusted links and to report unexpected Safari crashes to security teams.
Patch Information
Apple released fixes in Safari 18.6, iOS 18.6, iPadOS 18.6, iPadOS 17.7.9, macOS Sequoia 15.6, tvOS 18.6, visionOS 2.6, and watchOS 11.6. Refer to the vendor bulletins: Apple Support Advisory #124147, #124148, #124149, #124152, #124153, #124154, and #124155. Debian users should apply the Debian LTS Announcement August 2025 updates for affected WebKit packages.
Workarounds
- Restrict Safari usage on unpatched devices and prefer alternative browsers only where WebKit is not the underlying engine (note that iOS applications generally rely on WebKit).
- Use content filtering and DNS security controls to block access to known malicious domains delivering crafted web content.
- Disable JavaScript on untrusted sites through Safari site-specific settings where operationally feasible until patches are applied.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
