CVE-2026-84562: Apple macOS Race Condition Vulnerability

CVE-2026-84562 Overview

CVE-2026-84562 is a race condition vulnerability in Apple macOS that allows a local application to access protected user data. Apple addressed the issue by adding additional validation and shipped the fix in macOS Tahoe 26.6. The flaw is categorized as a concurrent execution flaw using shared resources with improper synchronization [CWE-362].

Exploitation requires local access and high attack complexity, and it does not require user interaction. Successful exploitation compromises confidentiality of protected user data without affecting integrity or availability.

Critical Impact
A local application can win a timing race against macOS access checks and read protected user data that Transparency, Consent, and Control (TCC) or similar controls would normally block.

Affected Products

Apple macOS versions prior to macOS Tahoe 26.6
Systems where third-party applications can execute with standard user privileges
macOS endpoints without the Apple security update applied

Discovery Timeline

2026-09-14 - CVE-2026-84562 published to the National Vulnerability Database
2026-09-17 - Last updated in the NVD database

Technical Details for CVE-2026-84562

Vulnerability Analysis

The vulnerability is a race condition in a macOS component that mediates access to protected user data. A local application executes operations in parallel with the access-check logic and manipulates the state between validation and use. This time-of-check to time-of-use (TOCTOU) pattern allows the application to reach protected resources that policy would otherwise deny.

Apple describes the fix as "additional validation," indicating that the original code path performed an authorization decision that could be invalidated by concurrent state changes before the resource was actually accessed. The updated logic re-verifies the relevant state at the point of access, closing the window an attacker can exploit.

Protected user data on macOS typically includes files and directories governed by TCC, such as documents, downloads, calendar entries, contacts, and photo libraries. Bypassing these controls undermines a core privacy boundary of the operating system.

Root Cause

The root cause is missing synchronization between an authorization check and the subsequent use of the authorized resource. Because both operations were not performed atomically, a second thread or process could alter the relevant state during the interval. The condition maps directly to [CWE-362], Concurrent Execution using Shared Resource with Improper Synchronization.

Attack Vector

An attacker must first run code as a local user with low privileges on the target macOS system. The exploit primitive is a timing race, which requires precise scheduling and repeated attempts, reflected in the high attack complexity of the CVSS vector. No user interaction is required once the malicious application is running.

A successful race allows the attacker's application to read protected user data outside its granted TCC entitlements. The scope is unchanged, and only confidentiality is impacted.

No public proof-of-concept or exploit code is available in Exploit-DB or vendor references at this time.

Detection Methods for CVE-2026-84562

Indicators of Compromise

Unsigned or newly installed applications repeatedly invoking file-access APIs against directories protected by TCC such as ~/Documents, ~/Downloads, ~/Library/Calendars, and ~/Library/Application Support/AddressBook.
Processes generating high volumes of open, stat, and readlink system calls in tight loops targeting the same protected paths.
Applications accessing protected user data without corresponding TCC prompts or entries in the user's Privacy database.

Detection Strategies

Baseline normal per-process access patterns to TCC-protected directories and alert on statistical anomalies such as sudden bursts of concurrent access attempts.
Correlate process execution telemetry with TCC decision logs from /Library/Application Support/com.apple.TCC/ to identify data access that bypassed prompts.
Monitor for unsigned binaries, developer-signed binaries, or Gatekeeper-quarantined applications performing sensitive file reads shortly after first launch.

Monitoring Recommendations

Forward macOS Endpoint Security Framework (ESF) events for file open, exec, and TCC-related subsystems to a central analytics platform.
Track macOS build versions across the fleet and alert on endpoints running versions older than macOS Tahoe 26.6.
Review privacy pane changes and TCC database modifications on managed endpoints on a scheduled basis.

How to Mitigate CVE-2026-84562

Immediate Actions Required

Update all affected macOS systems to macOS Tahoe 26.6 or later as documented in the Apple Support Article.
Inventory macOS endpoints and prioritize devices that handle regulated or sensitive user data.
Restrict installation of untrusted third-party applications through Mobile Device Management (MDM) policies while patching is in progress.

Patch Information

Apple released the fix in macOS Tahoe 26.6. The vendor addressed the race condition by adding additional validation in the affected code path. Details are published in the Apple Support Article. Administrators should deploy the update through Software Update, MDM commands, or the softwareupdate command-line utility.

Workarounds

Apply the vendor patch. Apple has not published a supported workaround for this issue.
Reduce local attack surface by limiting standard-user ability to install and execute unsigned applications.
Enforce application allowlisting and Gatekeeper policies through MDM to prevent execution of untrusted binaries capable of staging the race.

bash

# Verify macOS build and trigger update installation
sw_vers -productVersion
sudo softwareupdate --install --all --restart