CVE-2022-42856: Apple Safari RCE Vulnerability

CVE-2022-42856 Overview

CVE-2022-42856 is a type confusion vulnerability in Apple WebKit that allows attackers to execute arbitrary code through maliciously crafted web content. This vulnerability affects the WebKit browser engine used across multiple Apple platforms including Safari, iOS, iPadOS, macOS, and tvOS. The flaw stems from improper state handling within WebKit, which can be exploited when a user visits a malicious webpage.

Critical Impact

This vulnerability has been confirmed as actively exploited in the wild against iOS versions prior to iOS 15.1. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, indicating confirmed exploitation by threat actors targeting Apple device users.

Affected Products

• Apple Safari (versions prior to 16.2)
• Apple iOS and iPadOS (versions prior to 15.7.2 and 16.1.2)
• Apple macOS Ventura (versions prior to 13.1)
• Apple tvOS (versions prior to 16.2)

Discovery Timeline

• December 15, 2022 - CVE-2022-42856 published to NVD
• October 23, 2025 - Last updated in NVD database

Technical Details for CVE-2022-42856

Vulnerability Analysis

This type confusion vulnerability (CWE-843) exists within Apple's WebKit rendering engine, which powers Safari and is used by all browsers on iOS and iPadOS due to Apple's platform requirements. Type confusion occurs when a program allocates or initializes a resource such as a pointer, object, or variable using one type, but later accesses that resource using an incompatible type. In the context of WebKit, this can lead to memory corruption when the JavaScript engine misinterprets the type of an object during execution.

The vulnerability is particularly dangerous because WebKit is a core system component that processes untrusted web content by design. Any user browsing to a malicious or compromised website could trigger the vulnerability without any additional interaction beyond visiting the page. Apple has acknowledged reports that this vulnerability was actively exploited against devices running iOS versions before iOS 15.1, suggesting targeted attacks were conducted in the wild prior to the patch release.

Root Cause

The root cause of CVE-2022-42856 is improper state handling within WebKit's JavaScript engine. When processing certain JavaScript operations, the engine fails to properly validate or maintain type information for objects. This allows an attacker to craft JavaScript code that causes the engine to treat an object as a different type than intended, leading to type confusion. The state management flaw means that under specific conditions, the engine's internal representation of an object's type becomes inconsistent with its actual memory layout, creating an exploitable condition.

Attack Vector

The attack vector for this vulnerability is network-based and requires user interaction in the form of visiting a malicious webpage. An attacker can exploit this vulnerability by:

1. Hosting malicious JavaScript code on a website under their control
2. Luring victims to visit the malicious site through phishing, malvertising, or watering hole attacks
3. The malicious JavaScript triggers the type confusion in WebKit
4. Successful exploitation allows the attacker to execute arbitrary code with the privileges of the WebKit process

The exploitation does not require authentication or special privileges. Given that this vulnerability was actively exploited before iOS 15.1, attackers have demonstrated the ability to weaponize this flaw for targeted attacks. The type confusion can potentially be chained with sandbox escapes or privilege escalation vulnerabilities to achieve full device compromise.

Detection Methods for CVE-2022-42856

Indicators of Compromise

• Unusual WebKit or Safari process crashes with memory corruption signatures
• Unexpected outbound network connections from browser processes to unknown domains
• Evidence of JavaScript-based exploitation attempts in browser logs or network traffic
• Anomalous behavior from applications using WebKit for content rendering

Detection Strategies

• Monitor for crash reports related to WebKit or Safari that indicate type confusion or memory corruption
• Implement network monitoring to detect connections to known malicious domains associated with WebKit exploitation
• Deploy endpoint detection solutions capable of identifying exploitation attempts targeting browser vulnerabilities
• Review system logs for unauthorized code execution or privilege escalation following web browsing activity

Monitoring Recommendations

• Enable and centralize crash reporting for WebKit-based applications across managed devices
• Implement web content filtering to block access to known malicious sites
• Monitor for indicators of post-exploitation activity such as unexpected process spawning from browser contexts
• Deploy SentinelOne agents on all Apple devices to detect behavioral anomalies indicative of exploitation

How to Mitigate CVE-2022-42856

Immediate Actions Required

• Update all Apple devices immediately to the patched versions: Safari 16.2, iOS 15.7.2, iOS 16.1.2, iPadOS 15.7.2, macOS Ventura 13.1, and tvOS 16.2
• Prioritize updates for devices that may have been exposed to untrusted web content
• Enable automatic updates on all Apple devices to receive future security patches promptly
• Review device logs for any indicators of prior exploitation attempts

Patch Information

Apple has released security updates addressing this vulnerability across all affected platforms. The patches improve state handling within WebKit to prevent type confusion exploitation. Organizations should apply the following updates as documented in Apple's security advisories:

• Apple Security Update HT213516 - iOS 16.1.2
• Apple Security Update HT213531 - macOS Ventura 13.1
• Apple Security Update HT213532 - tvOS 16.2
• Apple Security Update HT213535 - iOS 15.7.2 and iPadOS 15.7.2
• Apple Security Update HT213537 - Safari 16.2

Additional security guidance is available from CISA's Known Exploited Vulnerability entry for CVE-2022-42856.

Workarounds

• Restrict browsing to trusted websites until patches can be applied
• Consider using content blockers or disabling JavaScript in Safari for high-risk environments, though this may impact functionality
• Implement network-level filtering to block known malicious domains and suspicious web content
• Use mobile device management (MDM) to enforce update policies and restrict access to unpatched devices

# Verify macOS version includes the security patch
sw_vers -productVersion
# Should show 13.1 or later for macOS Ventura

# Verify Safari version on macOS
/Applications/Safari.app/Contents/MacOS/Safari --version
# Should show 16.2 or later

# Force software update check on macOS
softwareupdate --list