CVE-2023-42950: Apple Safari Use-After-Free Vulnerability

CVE-2023-42950 Overview

CVE-2023-42950 is a use after free vulnerability discovered in Apple's WebKit rendering engine, which powers Safari and other Apple platform browsers. The vulnerability exists due to improper memory management when processing web content, allowing attackers to potentially achieve arbitrary code execution on affected devices. When a user visits a maliciously crafted webpage, the vulnerability can be triggered, leading to memory corruption and subsequent code execution in the context of the browser process.

This vulnerability affects a wide range of Apple products including Safari, iOS, iPadOS, macOS, tvOS, and watchOS, making it a significant security concern across the entire Apple ecosystem. The flaw was addressed through improved memory management in the affected components.

Critical Impact

Processing maliciously crafted web content may lead to arbitrary code execution, potentially allowing attackers to compromise user devices across multiple Apple platforms.

Affected Products

• Apple Safari versions prior to 17.2
• Apple iOS and iPadOS versions prior to 17.2
• Apple macOS Sonoma versions prior to 14.2
• Apple tvOS versions prior to 10.2
• Apple watchOS versions prior to 10.2

Discovery Timeline

• 2024-03-28 - CVE CVE-2023-42950 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2023-42950

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a type of memory corruption vulnerability that occurs when a program continues to use a pointer after the memory it references has been freed. In the context of WebKit, the browser's rendering engine, this type of vulnerability is particularly dangerous because WebKit processes untrusted content from the web.

The vulnerability requires user interaction—specifically, a user must navigate to or be directed to a malicious webpage that contains specially crafted content designed to trigger the memory corruption. Once triggered, the attacker can potentially gain control of program execution flow, leading to arbitrary code execution with the privileges of the browser process.

Given that Safari and WebKit are deeply integrated into Apple's operating systems and handle sensitive browsing activities, successful exploitation could allow attackers to access sensitive user data, install malware, or pivot to additional attacks on the compromised system.

Root Cause

The root cause of CVE-2023-42950 lies in improper memory management within WebKit's processing of web content. Use after free vulnerabilities typically occur when:

1. Memory is allocated for an object
2. The memory is freed (deallocated)
3. The program subsequently attempts to use the freed memory through a dangling pointer

In this case, WebKit's handling of certain web content elements failed to properly track memory lifecycle, resulting in a scenario where freed memory could be accessed. Apple addressed this by implementing improved memory management to ensure proper tracking and handling of memory allocations during web content processing.

Attack Vector

The attack vector for CVE-2023-42950 is network-based and requires user interaction. An attacker could exploit this vulnerability through the following attack scenarios:

The exploitation requires an attacker to craft malicious web content that triggers the use after free condition in WebKit. This could be delivered through various means including phishing campaigns directing users to malicious websites, compromised legitimate websites serving exploit code, malicious advertisements (malvertising), or links shared through social engineering attacks. When a victim's browser processes the malicious content, the vulnerability is triggered, potentially allowing the attacker to execute arbitrary code on the target system.

Detection Methods for CVE-2023-42950

Indicators of Compromise

• Unexpected browser crashes or instability when visiting specific websites
• Unusual memory consumption patterns in Safari or WebKit-based applications
• Suspicious network connections originating from browser processes
• Anomalous process spawning from Safari or other WebKit applications

Detection Strategies

• Monitor for unusual WebKit process behavior including unexpected child process creation
• Implement endpoint detection and response (EDR) solutions to identify memory corruption exploitation attempts
• Review browser crash reports for patterns indicative of use after free exploitation
• Deploy web content filtering to block known malicious domains and content patterns

Monitoring Recommendations

• Enable and review Safari diagnostic reports for crash patterns
• Monitor system logs for unexpected WebKit process terminations and restarts
• Implement network monitoring to detect connections to suspicious domains after browser activity
• Use SentinelOne's behavioral AI engine to detect post-exploitation activities indicative of browser compromise

How to Mitigate CVE-2023-42950

Immediate Actions Required

• Update all Apple devices to the latest available operating system versions immediately
• Ensure Safari is updated to version 17.2 or later on all supported systems
• Educate users about the risks of visiting untrusted websites or clicking suspicious links
• Consider implementing content filtering and web security gateways to reduce exposure to malicious content

Patch Information

Apple has released security updates addressing this vulnerability across all affected products. Organizations and users should apply the following updates:

• Safari 17.2: Apple Security Update HT214039
• iOS 17.2 and iPadOS 17.2: Apple Security Update HT214035
• macOS Sonoma 14.2: Apple Security Update HT214036
• tvOS 17.2: Apple Security Update HT214040
• watchOS 10.2: Apple Security Update HT214041

Additional references are available from the Openwall OSS Security Archive and NetApp Security Advisory NTAP-20241018-0009.

Workarounds

• Use alternative browsers temporarily until patches can be applied (note: this may not be effective on iOS where all browsers use WebKit)
• Implement strict browsing policies limiting access to known-safe websites only
• Enable Safari's built-in security features including fraudulent website warnings
• Consider using a VPN with web filtering capabilities to add an additional layer of protection

# Verify Safari version on macOS
/Applications/Safari.app/Contents/MacOS/Safari --version

# Check for available software updates on macOS
softwareupdate --list

# Install all available updates
sudo softwareupdate --install --all