CVE-2024-27833: Apple Safari RCE Vulnerability

CVE-2024-27833 Overview

CVE-2024-27833 is an integer overflow vulnerability [CWE-190] affecting Apple Safari and multiple Apple operating systems. The flaw resides in web content processing, where insufficient input validation allows numeric values to overflow during computation. Processing maliciously crafted web content may lead to arbitrary code execution on the targeted device.

Apple addressed the issue with improved input validation in Safari 17.5, iOS 16.7.8, iPadOS 16.7.8, iOS 17.5, iPadOS 17.5, tvOS 17.5, and visionOS 1.2.

Critical Impact

Successful exploitation enables arbitrary code execution in the context of the browser process, giving attackers a foothold for further compromise of the device.

Affected Products

• Apple Safari (prior to 17.5)
• Apple iOS and iPadOS (prior to 16.7.8 and 17.5)
• Apple tvOS (prior to 17.5) and visionOS (prior to 1.2)

Discovery Timeline

• 2024-06-10 - CVE-2024-27833 published to NVD
• 2026-04-02 - Last updated in NVD database

Technical Details for CVE-2024-27833

Vulnerability Analysis

The vulnerability is an integer overflow in the handling of web content. When Safari or the underlying WebKit-based renderer processes attacker-controlled input, an arithmetic operation produces a value that exceeds the bounds of its integer type. The truncated or wrapped value is then used in subsequent memory operations.

This miscalculation can lead to undersized buffer allocations or incorrect index computations. Attackers leverage the resulting memory corruption primitive to influence program control flow and execute arbitrary code in the browser context. User interaction is required, typically by enticing the victim to visit a malicious webpage.

Root Cause

The root cause is missing or insufficient input validation before performing arithmetic operations on size or length values derived from web content. Apple's fix introduces improved input validation to detect and reject values that would trigger overflow conditions before they are used in memory management routines.

Attack Vector

Exploitation occurs over the network through a crafted webpage. An attacker hosts malicious content on a website or delivers it via a compromised page, advertisement, or phishing link. When the victim opens the page in a vulnerable Safari or WebKit-based application, the integer overflow is triggered during content parsing. Successful exploitation typically chains with sandbox escapes for broader system impact.

The vulnerability is described in prose only — no public proof-of-concept code is available. Refer to the Apple Security Advisory 120896 and the Full Disclosure Security Report for additional technical context.

Detection Methods for CVE-2024-27833

Indicators of Compromise

• Unexpected Safari or WebKit process crashes with signatures consistent with memory corruption (EXC_BAD_ACCESS, segmentation faults during web content rendering).
• Outbound connections from browser processes to newly registered or low-reputation domains immediately after page navigation.
• Spawning of unexpected child processes from Safari, WebContent, or com.apple.WebKit.WebContent services.

Detection Strategies

• Monitor endpoint telemetry for browser process anomalies, including atypical memory allocations and crash patterns in WebKit rendering processes.
• Apply web filtering and threat intelligence feeds to block known malicious URLs delivering exploit content.
• Correlate browser crash events with subsequent suspicious process activity to identify exploitation attempts.

Monitoring Recommendations

• Track Safari and iOS version inventory across managed devices to identify systems running pre-patch builds.
• Alert on repeated WebKit process restarts on the same device within short time windows.
• Log DNS and HTTP requests preceding browser crashes to identify exploit-delivery infrastructure.

How to Mitigate CVE-2024-27833

Immediate Actions Required

• Update Safari to version 17.5 and Apple operating systems to iOS/iPadOS 16.7.8, iOS/iPadOS 17.5, tvOS 17.5, or visionOS 1.2.
• Enforce patched versions via Mobile Device Management (MDM) policies for organization-managed Apple devices.
• Educate users to avoid clicking unsolicited links and to report unexpected browser crashes.

Patch Information

Apple released fixes across multiple platforms. Review the relevant advisories: Apple Security Update HT214100, HT214101, HT214102, HT214103, and HT214108. The fix introduces improved input validation to prevent the integer overflow condition.

Workarounds

• Restrict browsing to trusted sites via enterprise web proxy or content filtering until patches are deployed.
• Disable JavaScript on untrusted sites or use Safari's Lockdown Mode on supported devices to reduce attack surface.
• Isolate unpatched devices from sensitive network segments until updates are applied.

# Verify Safari version on macOS
defaults read /Applications/Safari.app/Contents/Info.plist CFBundleShortVersionString

# Check iOS/iPadOS version via MDM query or on-device
# Settings > General > About > Software Version (must be 17.5 or 16.7.8+)