CVE-2026-20670: Apple macOS Information Disclosure Issue

CVE-2026-20670 Overview

CVE-2026-20670 is an authorization bypass vulnerability affecting Apple macOS. The flaw stems from improper state management in the authorization component, which allows a malicious application to bypass security controls and access sensitive user data. This vulnerability requires local access and low privileges to exploit, making it a concern for environments where untrusted applications may be installed.

Critical Impact

A malicious application running on an affected macOS system can bypass authorization checks and gain unauthorized access to sensitive user data, potentially leading to data theft or privacy violations.

Affected Products

• Apple macOS Sonoma (versions prior to 14.8.4)
• Apple macOS Tahoe (versions prior to 26.3)

Discovery Timeline

• 2026-03-25 - CVE-2026-20670 published to NVD
• 2026-03-26 - Last updated in NVD database

Technical Details for CVE-2026-20670

Vulnerability Analysis

This vulnerability is classified as an authorization bypass resulting from improper state management within macOS. The flaw allows applications to circumvent the standard authorization mechanisms that protect sensitive user data. When an application makes requests to access protected resources, the macOS security framework should verify that proper entitlements and user consent have been obtained. However, due to the state management issue, these authorization checks can be bypassed under certain conditions.

The attack requires local access to the target system, meaning an attacker would need to either have physical access or deploy a malicious application through social engineering or supply chain compromise. Once a malicious application is executing on the vulnerable system, it can leverage this flaw to access sensitive user data that would normally be protected by macOS privacy controls such as TCC (Transparency, Consent, and Control).

Root Cause

The root cause of CVE-2026-20670 is improper state management within the macOS authorization subsystem. State management flaws occur when the system fails to properly track or validate the authorization state during access control decisions. This can result in the system incorrectly believing that authorization has been granted when it has not, or failing to enforce authorization requirements at critical checkpoints.

In macOS, the authorization framework relies on maintaining accurate state information about what permissions have been granted to applications. When this state information becomes inconsistent or is improperly validated, applications may be able to access resources beyond their intended permissions.

Attack Vector

The attack vector for CVE-2026-20670 is local. An attacker must first gain the ability to execute code on the target macOS system, typically through a malicious application. The attack flow would proceed as follows:

1. The attacker distributes a malicious application that appears legitimate
2. The victim installs and runs the application
3. The application exploits the state management flaw to bypass authorization checks
4. Sensitive user data becomes accessible to the application without proper consent

This vulnerability does not require any user interaction beyond the initial execution of the malicious application. The technical details of the specific exploitation method have not been publicly disclosed by Apple, in keeping with their security advisory practices. For more information, refer to the Apple Support Advisory #126348 and Apple Support Advisory #126350.

Detection Methods for CVE-2026-20670

Indicators of Compromise

• Unusual application access to TCC-protected directories such as ~/Library/Application Support, ~/Desktop, ~/Documents, or ~/Downloads
• Applications accessing sensitive data stores like Contacts, Calendar, or Photos without corresponding TCC consent records
• Unexpected entries or missing entries in the TCC database (~/Library/Application Support/com.apple.TCC/TCC.db)
• Applications running with access to protected user data that have no corresponding privacy permission prompts in System Settings

Detection Strategies

• Monitor the Unified Log for authorization-related events and anomalies using log stream --predicate 'subsystem == "com.apple.TCC"'
• Review application entitlements for installed software to identify potentially malicious applications
• Implement endpoint detection solutions that monitor for unauthorized access to protected file locations
• Audit installed applications against known good software inventories

Monitoring Recommendations

• Enable detailed audit logging for file system access in security-sensitive environments
• Deploy endpoint detection and response (EDR) solutions capable of monitoring macOS privacy framework events
• Regularly review application behavior patterns for anomalous data access
• Implement application allowlisting to prevent unauthorized applications from executing

How to Mitigate CVE-2026-20670

Immediate Actions Required

• Update macOS Sonoma to version 14.8.4 or later immediately
• Update macOS Tahoe to version 26.3 or later immediately
• Audit installed applications and remove any untrusted or unnecessary software
• Review TCC permissions in System Settings > Privacy & Security and revoke access for suspicious applications

Patch Information

Apple has addressed this vulnerability with improved state management in macOS Sonoma 14.8.4 and macOS Tahoe 26.3. Organizations should prioritize deployment of these updates, particularly on systems that handle sensitive data or are exposed to potentially untrusted applications.

Official security advisories are available:

• Apple Support Advisory #126348
• Apple Support Advisory #126350

Workarounds

• Restrict application installation to only trusted sources (Mac App Store or identified developers) via Gatekeeper settings
• Implement Mobile Device Management (MDM) policies to control which applications can be installed on enterprise devices
• Enable and enforce FileVault encryption to protect data at rest
• Apply principle of least privilege by running with standard user accounts rather than administrator accounts

# Configuration example
# Verify current macOS version to confirm patch status
sw_vers -productVersion

# Check for pending software updates
softwareupdate --list

# Apply available security updates
softwareupdate --install --all

# Review TCC database for suspicious entries (requires Full Disk Access)
sqlite3 ~/Library/Application\ Support/com.apple.TCC/TCC.db "SELECT client,service,auth_value FROM access;"