CVE-2023-28205: Apple Safari Use-After-Free Vulnerability

CVE-2023-28205 Overview

CVE-2023-28205 is a critical use after free vulnerability affecting Apple's WebKit browser engine across multiple Apple products including Safari, iOS, iPadOS, and macOS. This memory corruption vulnerability allows attackers to achieve arbitrary code execution when a user processes maliciously crafted web content. Apple has confirmed that this vulnerability has been actively exploited in the wild, and it has been added to CISA's Known Exploited Vulnerabilities (KEV) catalog.

Critical Impact

This actively exploited vulnerability enables remote attackers to execute arbitrary code on affected Apple devices through malicious web content, potentially leading to complete device compromise.

Affected Products

• Apple Safari (versions prior to 16.4.1)
• Apple iOS and iPadOS (versions prior to 15.7.5 and 16.4.1)
• Apple macOS Ventura (versions prior to 13.3.1)

Discovery Timeline

• April 10, 2023 - CVE-2023-28205 published to NVD
• October 23, 2025 - Last updated in NVD database

Technical Details for CVE-2023-28205

Vulnerability Analysis

This use after free (UAF) vulnerability resides in Apple's WebKit rendering engine, which is the core browser engine powering Safari and all iOS/iPadOS browsers. The vulnerability occurs when WebKit improperly manages memory during the processing of web content, allowing an attacker to reference memory after it has been freed.

In use after free scenarios, when a program continues to use a pointer after the memory it references has been deallocated, the memory may be reallocated for a different purpose. An attacker can manipulate this condition to gain control over program execution flow. In the context of WebKit, successful exploitation allows the attacker to execute arbitrary code within the context of the browser process, potentially leading to full system compromise.

The vulnerability is particularly dangerous because it can be triggered simply by visiting a malicious website or viewing attacker-controlled web content, requiring no additional user interaction beyond normal web browsing activity.

Root Cause

The root cause is a memory management flaw in WebKit where memory is accessed after being freed (CWE-416: Use After Free). This occurs when the WebKit engine fails to properly track object lifetimes during web content processing, leading to dangling pointer references that can be exploited by attackers.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker can exploit this vulnerability by:

1. Crafting a malicious web page containing specially designed content that triggers the use after free condition
2. Luring a victim to visit the malicious page through phishing, watering hole attacks, or malicious advertisements
3. When the victim's browser renders the malicious content, the vulnerability is triggered
4. The attacker gains arbitrary code execution capabilities within the browser context

The exploitation requires no special privileges and has low attack complexity, making it an attractive target for threat actors. Apple has confirmed active exploitation of this vulnerability in the wild.

Detection Methods for CVE-2023-28205

Indicators of Compromise

• Unusual Safari or WebKit process crashes or unexpected behavior
• Anomalous network connections originating from browser processes to unknown destinations
• Unexpected child processes spawned by Safari or WebKit-based applications
• Memory corruption artifacts in crash logs referencing WebKit components

Detection Strategies

• Monitor for Safari and WebKit crash reports that indicate memory corruption or use after free conditions
• Implement endpoint detection rules for suspicious process chains originating from browser processes
• Deploy web filtering solutions to block known malicious domains associated with WebKit exploits
• Review system logs for indicators of post-exploitation activity following browser usage

Monitoring Recommendations

• Enable comprehensive logging for Safari and system processes on all Apple devices
• Implement network monitoring to detect connections to known command and control infrastructure
• Configure endpoint detection and response (EDR) solutions to alert on browser-based code execution attempts
• Monitor CISA KEV catalog and Apple security advisories for updates related to this vulnerability

How to Mitigate CVE-2023-28205

Immediate Actions Required

• Update all Apple devices to patched software versions immediately (Safari 16.4.1, iOS 15.7.5/16.4.1, iPadOS 15.7.5/16.4.1, macOS Ventura 13.3.1)
• Enable automatic updates on all Apple devices to ensure timely patching of future vulnerabilities
• Implement mobile device management (MDM) policies to enforce software updates across organizational devices
• Review and restrict web browsing on unpatched devices until updates can be applied

Patch Information

Apple has released security updates to address this vulnerability with improved memory management. The following versions contain the fix:

• Safari: Version 16.4.1 - See Apple Support Document HT213720
• iOS/iPadOS: Versions 15.7.5 and 16.4.1 - See Apple Support Document HT213721 and Apple Support Document HT213722
• macOS Ventura: Version 13.3.1 - See Apple Support Document HT213723

This vulnerability is listed in the CISA Known Exploited Vulnerabilities Catalog, which mandates federal agencies to remediate by specified deadlines.

Workarounds

• Limit browsing activity on unpatched devices to trusted websites only
• Consider using alternative browsers on macOS (though iOS browsers all use WebKit)
• Implement web content filtering at the network perimeter to block potentially malicious content
• Disable JavaScript in Safari settings as a temporary measure (note: this will break many websites)

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

# Check macOS version
sw_vers -productVersion

# Enable automatic updates via command line
sudo softwareupdate --schedule on