CVE-2026-28879: Apple iPadOS Use-After-Free Vulnerability

CVE-2026-28879 Overview

CVE-2026-28879 is a use-after-free vulnerability affecting multiple Apple operating systems including iOS, iPadOS, macOS, tvOS, visionOS, and watchOS. The vulnerability exists in the memory management component used when processing web content. When a user visits a maliciously crafted webpage, the vulnerable component may access memory that has already been freed, leading to an unexpected process crash and denial of service condition.

Critical Impact

Processing maliciously crafted web content may lead to an unexpected process crash, causing denial of service across iPhone, iPad, Mac, Apple TV, Apple Watch, and Apple Vision Pro devices.

Affected Products

• Apple iOS 18.7.7 and earlier, iOS 26.4 and earlier
• Apple iPadOS 18.7.7 and earlier, iPadOS 26.4 and earlier
• Apple macOS Sequoia 15.7.5, macOS Sonoma 14.8.5, macOS Tahoe 26.4
• Apple tvOS 26.4 and earlier
• Apple visionOS 26.4 and earlier
• Apple watchOS 26.4 and earlier

Discovery Timeline

• 2026-03-25 - CVE-2026-28879 published to NVD
• 2026-03-25 - Last updated in NVD database

Technical Details for CVE-2026-28879

Vulnerability Analysis

This use-after-free vulnerability (CWE-416) occurs in the memory management subsystem responsible for handling web content across Apple's operating system family. Use-after-free vulnerabilities arise when a program continues to reference memory after it has been freed, which can lead to undefined behavior including crashes, data corruption, or potentially code execution in more severe cases.

In this instance, the vulnerability is triggered when processing maliciously crafted web content. The attack requires network access and user interaction—specifically, a victim must be enticed to visit or load attacker-controlled web content. While the immediate impact is denial of service through process crashes, use-after-free vulnerabilities historically present a risk of escalation to arbitrary code execution if an attacker can control the contents of the freed memory region.

The vulnerability affects Apple's entire ecosystem of devices, from mobile platforms (iOS, iPadOS) to desktop (macOS) and peripheral devices (tvOS, visionOS, watchOS), indicating the vulnerable code resides in a shared web rendering component.

Root Cause

The root cause is improper memory management in the web content processing component. When certain web content is processed, memory is freed but pointers to that memory region are not properly invalidated. Subsequent operations may then attempt to use these dangling pointers, accessing freed memory regions. Apple addressed this issue with improved memory management to ensure proper tracking and invalidation of memory references.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker would need to:

1. Craft malicious web content designed to trigger the use-after-free condition
2. Host the malicious content on a web server or inject it into a legitimate website
3. Entice the victim to visit the malicious page through phishing, social engineering, or compromised advertisements
4. Upon loading the crafted content, the vulnerable memory management code is triggered, causing a process crash

The vulnerability can be exploited remotely but requires the victim to actively load the malicious content. The primary impact is availability loss through denial of service, affecting the stability of web-rendering processes on affected Apple devices.

Detection Methods for CVE-2026-28879

Indicators of Compromise

• Unexpected crashes of web browsers or web-based applications on Apple devices
• Repeated WebContent or Safari process terminations in system logs
• Crash reports indicating memory access violations in web rendering components
• User reports of browser instability when visiting specific websites

Detection Strategies

• Monitor system logs for WebContent process crashes with memory-related exception codes
• Implement network monitoring to detect access to known malicious URLs serving exploit content
• Review crash reports in Apple's Console application for patterns indicating exploitation attempts
• Deploy endpoint detection solutions capable of identifying abnormal web rendering behavior

Monitoring Recommendations

• Enable crash reporting and centralized log collection across managed Apple devices
• Monitor for spikes in browser-related crashes that could indicate active exploitation
• Implement web filtering to block access to suspicious or newly registered domains
• Track device health metrics including application stability scores

How to Mitigate CVE-2026-28879

Immediate Actions Required

• Update all Apple devices to the patched operating system versions immediately
• Prioritize updates for devices that regularly browse untrusted web content
• Enable automatic updates on managed devices to ensure timely patch deployment
• Consider restricting web browsing on sensitive systems until patches are applied

Patch Information

Apple has released security updates to address this vulnerability across all affected platforms. Organizations should update to the following versions:

• iOS 18.7.7 or iOS 26.4 - Apple Security Update #126792
• iPadOS 18.7.7 or iPadOS 26.4 - Apple Security Update #126793
• macOS Sequoia 15.7.5 - Apple Security Update #126794
• macOS Sonoma 14.8.5 - Apple Security Update #126795
• macOS Tahoe 26.4 - Apple Security Update #126796
• tvOS 26.4 - Apple Security Update #126797
• visionOS 26.4 - Apple Security Update #126798
• watchOS 26.4 - Apple Security Update #126799

Workarounds

• Limit web browsing to trusted websites until patches can be applied
• Use content blockers or ad blockers to reduce exposure to potentially malicious web content
• Disable JavaScript in browser settings for non-essential browsing (may impact functionality)
• Implement network-level web filtering to block known malicious domains

# Check current macOS version
sw_vers -productVersion

# Initiate software update on macOS
softwareupdate --install --all

# List available updates
softwareupdate --list