CVE-2024-27851: Apple Safari RCE Vulnerability

CVE-2024-27851 Overview

CVE-2024-27851 is a memory corruption vulnerability affecting Apple's WebKit browser engine across multiple Apple platforms. The vulnerability stems from improper bounds checking when processing maliciously crafted web content, which can be exploited to achieve arbitrary code execution on affected devices. This vulnerability affects Safari, iOS, iPadOS, macOS, tvOS, visionOS, and watchOS, presenting a significant attack surface across Apple's entire ecosystem.

Critical Impact

Processing maliciously crafted web content may lead to arbitrary code execution, potentially allowing attackers to compromise user devices through malicious websites or web-based attacks.

Affected Products

• Apple Safari versions prior to 17.5
• Apple iOS and iPadOS versions prior to 17.5
• Apple macOS Sonoma versions prior to 14.5
• Apple tvOS versions prior to 17.5
• Apple visionOS versions prior to 1.2
• Apple watchOS versions prior to 10.5

Discovery Timeline

• June 10, 2024 - CVE-2024-27851 published to NVD
• November 4, 2025 - Last updated in NVD database

Technical Details for CVE-2024-27851

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), indicating that the underlying issue involves memory operations that fail to properly validate buffer boundaries. When WebKit processes specially crafted web content, the lack of proper bounds checking allows memory operations to exceed allocated buffer limits, leading to memory corruption.

The vulnerability requires user interaction—specifically, a victim must visit a malicious webpage or process malicious web content. Once triggered, the memory corruption can be leveraged by an attacker to execute arbitrary code within the context of the affected application or operating system, potentially leading to complete device compromise.

Root Cause

The root cause of CVE-2024-27851 lies in insufficient bounds validation within WebKit's content processing routines. When handling certain types of web content, the engine fails to verify that memory operations remain within the allocated buffer boundaries. This oversight allows attackers to craft specific web content that triggers out-of-bounds memory access, corrupting adjacent memory regions and enabling code execution.

Attack Vector

This vulnerability is exploitable over the network without requiring authentication. An attacker can host malicious web content on a website or inject it into legitimate sites through techniques such as malvertising or compromised third-party resources. The attack flow typically involves:

1. Attacker crafts malicious web content designed to trigger the bounds check failure
2. Victim visits the malicious webpage through Safari or an app using WebKit
3. WebKit processes the content, triggering memory corruption
4. Attacker achieves arbitrary code execution on the victim's device

The vulnerability's network-based attack vector combined with the ubiquity of web browsing makes it particularly dangerous. Successful exploitation could lead to data theft, malware installation, or complete device takeover.

Detection Methods for CVE-2024-27851

Indicators of Compromise

• Unusual Safari or WebKit process crashes or restarts
• Unexpected network connections originating from browser processes to unknown destinations
• Memory access violation logs or crash reports referencing WebKit components
• Anomalous child processes spawned by Safari or other WebKit-enabled applications

Detection Strategies

• Monitor for WebKit crash reports that indicate memory corruption patterns or out-of-bounds access
• Implement network monitoring to detect connections to known malicious infrastructure
• Deploy endpoint detection solutions capable of identifying memory exploitation techniques
• Analyze browser history and cache for suspicious or obfuscated web content

Monitoring Recommendations

• Enable crash reporting and analyze WebKit-related crashes for exploitation patterns
• Implement web filtering to block access to known malicious domains
• Monitor system logs for unusual process behavior associated with Safari and WebKit
• Utilize SentinelOne's behavioral AI to detect post-exploitation activities indicative of code execution

How to Mitigate CVE-2024-27851

Immediate Actions Required

• Update all Apple devices to the patched versions: Safari 17.5, iOS/iPadOS 17.5, macOS Sonoma 14.5, tvOS 17.5, visionOS 1.2, and watchOS 10.5
• Enable automatic updates to ensure timely delivery of future security patches
• Consider using content blockers or web filtering solutions to reduce exposure to malicious web content
• Educate users about the risks of visiting untrusted websites

Patch Information

Apple has addressed this vulnerability by implementing improved bounds checks in the affected software. Security patches are available in the following releases:

• Safari 17.5 - Apple Security Advisory HT214103
• iOS 17.5 and iPadOS 17.5 - Apple Security Advisory HT214101
• macOS Sonoma 14.5 - Apple Security Advisory HT214106
• tvOS 17.5 - Apple Security Advisory HT214102
• visionOS 1.2 - Apple Security Advisory HT214108
• watchOS 10.5 - Apple Security Advisory HT214104

Organizations should prioritize patching all Apple devices within their environment, particularly those used for web browsing or handling sensitive data.

Workarounds

• Use alternative browsers that do not rely on WebKit when possible on desktop systems
• Implement network-level content filtering to block known malicious sites
• Restrict web browsing on critical systems until patches can be applied
• Enable JavaScript blocking or use privacy-focused browser extensions to limit attack surface

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

# Check iOS/iPadOS version
# Settings > General > About > Software Version
# Ensure version is 17.5 or later

# macOS software update via command line
softwareupdate --list
softwareupdate --install --all