CVE-2026-28834: Apple macOS Race Condition Vulnerability

CVE-2026-28834 Overview

CVE-2026-28834 is a race condition vulnerability in Apple macOS that affects state handling within the operating system. The vulnerability exists due to improper synchronization of concurrent operations, which can be exploited by a malicious application to cause unexpected system termination. Apple has addressed this issue with improved state handling in the affected macOS versions.

Critical Impact

A malicious application running on affected macOS systems can exploit this race condition to cause unexpected system termination, resulting in denial of service conditions that may lead to data loss and system instability.

Affected Products

• macOS Sequoia versions prior to 15.7.5
• macOS Sonoma versions prior to 14.8.5
• macOS Tahoe versions prior to 26.4

Discovery Timeline

• 2026-03-25 - CVE-2026-28834 published to NVD
• 2026-03-25 - Last updated in NVD database

Technical Details for CVE-2026-28834

Vulnerability Analysis

This vulnerability is classified as CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization), commonly known as a race condition. The flaw exists within macOS's state handling mechanisms where concurrent operations are not properly synchronized, creating a window of opportunity for exploitation.

Race conditions occur when the outcome of a process depends on the sequence or timing of uncontrollable events. In this case, the vulnerability requires local access and involves high attack complexity due to the timing-dependent nature of the exploit. When successfully exploited, an attacker can cause the system to enter an inconsistent state, triggering an unexpected system termination.

The attack requires no privileges or user interaction to execute once a malicious application is running on the system. The impact is primarily focused on system availability, potentially causing denial of service conditions that affect the entire system.

Root Cause

The root cause of CVE-2026-28834 lies in improper state handling within macOS when dealing with concurrent operations. The operating system fails to adequately synchronize access to shared resources or state information, creating a Time-of-Check to Time-of-Use (TOCTOU) window that can be exploited to corrupt system state and trigger a crash.

Apple's fix implements improved state handling mechanisms that properly synchronize concurrent access to the affected components, eliminating the race condition window.

Attack Vector

The attack vector for CVE-2026-28834 is local, meaning an attacker needs to execute code on the target macOS system. The exploitation scenario involves:

1. A malicious application is installed and executed on the target macOS system
2. The application initiates concurrent operations targeting the vulnerable state handling code
3. By precisely timing these operations, the attacker exploits the race condition
4. The race condition corrupts internal state, causing the system to terminate unexpectedly

Due to the timing-sensitive nature of race conditions, successful exploitation may require multiple attempts. The vulnerability can be triggered without requiring elevated privileges or user interaction beyond running the malicious application.

Detection Methods for CVE-2026-28834

Indicators of Compromise

• Unexpected system crashes or kernel panics on macOS systems without apparent hardware cause
• Suspicious applications exhibiting high CPU usage or unusual threading behavior
• Repeated system restarts within short timeframes without user initiation
• Crash logs indicating state corruption or synchronization errors in system components

Detection Strategies

• Monitor macOS crash reports and kernel panic logs for patterns indicative of race condition exploitation
• Implement application whitelisting to prevent unauthorized applications from running on critical systems
• Deploy endpoint detection solutions capable of identifying abnormal application behavior and threading patterns
• Review system logs for unusual application activity that precedes system terminations

Monitoring Recommendations

• Enable verbose logging for system events and application behavior on macOS endpoints
• Configure alerting for repeated system crashes or unexpected terminations across managed devices
• Implement centralized log collection from macOS systems to identify exploitation patterns across the fleet
• Monitor for installation of unknown or suspicious applications that could be exploitation attempts

How to Mitigate CVE-2026-28834

Immediate Actions Required

• Update affected macOS systems to patched versions: Sequoia 15.7.5, Sonoma 14.8.5, or Tahoe 26.4
• Review installed applications on affected systems and remove any untrusted or suspicious software
• Limit local code execution capabilities by enforcing application signing requirements
• Implement network segmentation to contain potential impact from compromised systems

Patch Information

Apple has released security updates addressing this vulnerability in the following versions:

• macOS Sequoia 15.7.5 - Apple Security Advisory #126794
• macOS Sonoma 14.8.5 - Apple Security Advisory #126795
• macOS Tahoe 26.4 - Apple Security Advisory #126796

Organizations should prioritize deploying these updates to all affected macOS systems through standard patch management processes. The updates implement improved state handling that properly synchronizes concurrent operations, eliminating the race condition.

Workarounds

• Restrict application installation to only trusted, signed applications from verified sources
• Enable Gatekeeper and ensure it is configured to allow only App Store and identified developer applications
• Implement strict user access controls to limit which users can install and execute applications
• Consider disabling or restricting untrusted applications until patching can be completed

# Verify macOS version to confirm patch status
sw_vers -productVersion

# Check Gatekeeper status
spctl --status

# Enable Gatekeeper if disabled
sudo spctl --master-enable

# Verify application signing requirements
spctl --assess --verbose /Applications/SuspiciousApp.app