CVE-2026-28830: Apple macOS Race Condition Vulnerability

CVE-2026-28830 Overview

CVE-2026-28830 is a race condition vulnerability in Apple macOS that allows a local application to access sensitive user data. Apple addressed the issue by adding additional validation in macOS Tahoe 26.4. The flaw is classified under [CWE-362] (Concurrent Execution using Shared Resource with Improper Synchronization).

Exploitation requires local access and user interaction, and the attack complexity is high. Despite these constraints, successful exploitation results in disclosure of sensitive user data stored on the system.

Critical Impact

A local application may bypass macOS access controls through a timing window and read sensitive user data without authorization.

Affected Products

• Apple macOS versions prior to macOS Tahoe 26.4
• Systems where untrusted local applications can execute
• macOS endpoints relying on default privacy and data access controls

Discovery Timeline

• 2026-05-11 - CVE-2026-28830 published to NVD
• 2026-05-12 - Last updated in NVD database

Technical Details for CVE-2026-28830

Vulnerability Analysis

The vulnerability is a race condition in macOS where a check on access to sensitive user data is separated from the use of that data. An attacker-controlled application can exploit the timing window between validation and access. Apple's advisory states the issue was addressed with additional validation, indicating the original code path did not adequately synchronize state between concurrent operations.

The attack vector is local with high complexity, reflecting the precise timing required to win the race. User interaction is required, suggesting the malicious app must be launched or triggered by the user. The impact is limited to confidentiality, with no integrity or availability consequences reported.

Given the EPSS data, observed exploitation likelihood is currently low. However, race conditions of this class are reliably weaponizable once the exact code path is identified.

Root Cause

The root cause is improper synchronization between a security check and the subsequent use of a shared resource, a classic Time-of-Check Time-of-Use (TOCTOU) pattern. Without atomic validation, a concurrent thread or process can alter the state observed by the check before the access occurs. Apple's fix adds further validation to close this window.

Attack Vector

A local attacker delivers a crafted application to the target system. The application races a privileged or protected operation to access user data that should be gated by macOS privacy controls. Because user interaction is required, the application must be executed by the target, typically through social engineering or bundling with otherwise benign software.

No public proof-of-concept code or exploit is currently available. Readers should refer to the Apple Support Article for vendor-supplied technical details.

Detection Methods for CVE-2026-28830

Indicators of Compromise

• Unsigned or newly installed applications performing rapid, repeated access attempts to protected user data directories such as ~/Library, ~/Documents, or TCC-protected paths
• Unexpected processes spawning multiple short-lived threads targeting the same file descriptors or system resources
• macOS endpoints running versions earlier than macOS Tahoe 26.4 with recently launched untrusted binaries

Detection Strategies

• Monitor for processes that perform high-frequency stat, open, or access system calls against sensitive user data paths within tight time windows
• Alert on applications attempting to read files immediately after privacy or entitlement checks complete
• Correlate user-initiated application launches with subsequent access to TCC-protected resources by non-Apple-signed binaries

Monitoring Recommendations

• Maintain an inventory of macOS endpoints and track those still running versions earlier than macOS Tahoe 26.4
• Enable Endpoint Security framework telemetry for file access and process events, and forward logs to a centralized analytics platform
• Review user-installed applications periodically and flag those requesting Full Disk Access or other broad privacy entitlements

How to Mitigate CVE-2026-28830

Immediate Actions Required

• Update all affected macOS systems to macOS Tahoe 26.4 or later as published in the Apple Support Article
• Restrict installation of unsigned and non-notarized applications through Gatekeeper policy enforcement
• Audit and remove unnecessary applications that hold Full Disk Access or TCC permissions on managed endpoints

Patch Information

Apple released the fix in macOS Tahoe 26.4. The patch adds additional validation to eliminate the race condition window. Refer to the Apple Support Article for the complete list of addressed issues and update instructions.

Workarounds

• Limit local execution of untrusted applications via Mobile Device Management (MDM) policies and application allowlisting
• Enforce least-privilege configuration for user accounts and review TCC entitlements granted to third-party software
• Avoid launching applications received from untrusted sources until the patch is applied

# Verify macOS version and confirm patch level
sw_vers -productVersion
# Expected output: 26.4 or higher

# List third-party kernel and system extensions for review
systemextensionsctl list