CVE-2026-20647: macOS Tahoe Information Disclosure Flaw

CVE-2026-20647 Overview

CVE-2026-20647 is an information disclosure vulnerability in macOS Tahoe that allows a malicious application to access sensitive user data due to insufficient data protection mechanisms. This vulnerability, classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor), could allow unauthorized apps to bypass expected privacy controls and retrieve confidential user information.

Critical Impact

A malicious application running on an affected macOS Tahoe system may be able to access sensitive user data, potentially exposing personal information, credentials, or other confidential data stored on the device.

Affected Products

• macOS Tahoe (versions prior to 26.3)

Discovery Timeline

• 2026-02-11 - CVE-2026-20647 published to NVD
• 2026-02-12 - Last updated in NVD database

Technical Details for CVE-2026-20647

Vulnerability Analysis

This vulnerability stems from inadequate data protection mechanisms within macOS Tahoe. The flaw allows applications to access sensitive user data that should be restricted and protected by the operating system's security controls. The issue requires local access to the affected system and user interaction (such as running a malicious application) for successful exploitation.

The vulnerability affects the confidentiality of user data, with high impact on data exposure while having no impact on system integrity or availability. This means that while an attacker cannot modify or delete data or disrupt system operations, they can potentially exfiltrate sensitive information stored on the affected macOS system.

Root Cause

The root cause of CVE-2026-20647 is classified as CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor). This indicates that the macOS data protection mechanisms failed to properly restrict access to sensitive user data, allowing unauthorized applications to read protected information that should have been isolated by the operating system's security boundaries.

Attack Vector

The attack requires local access to the target macOS Tahoe system. An attacker would need to convince a user to download and execute a malicious application, or compromise an existing application on the system. Once the malicious app is running, it can exploit the data protection weakness to access sensitive user data without proper authorization.

The exploitation scenario typically involves:

1. An attacker crafts or distributes a malicious macOS application
2. The victim downloads and executes the application (user interaction required)
3. The malicious app exploits the data protection flaw to access protected user data
4. Sensitive information is exfiltrated or logged by the attacker

No verified code examples are available for this vulnerability. For technical implementation details, refer to the Apple Support Article which provides additional context on the security fix.

Detection Methods for CVE-2026-20647

Indicators of Compromise

• Unusual application behavior involving access to protected user data directories
• Unexpected data access requests from applications that should not require such permissions
• Applications accessing sensitive data stores outside their normal sandboxed scope

Detection Strategies

• Monitor for applications attempting to access protected user data locations without appropriate entitlements
• Implement application allowlisting to prevent unauthorized applications from executing
• Review macOS system logs for unusual data access patterns from third-party applications
• Use endpoint detection solutions to identify suspicious application behavior

Monitoring Recommendations

• Enable enhanced logging for file system access events on sensitive data directories
• Configure SentinelOne or similar EDR solutions to alert on anomalous application data access patterns
• Regularly audit installed applications and their permissions
• Monitor for new or modified applications that could exploit this vulnerability

How to Mitigate CVE-2026-20647

Immediate Actions Required

• Update macOS Tahoe to version 26.3 or later immediately
• Review and audit applications currently installed on affected systems
• Restrict installation of untrusted applications through system policies
• Educate users about the risks of downloading and running applications from untrusted sources

Patch Information

Apple has addressed this vulnerability in macOS Tahoe 26.3 with improved data protection mechanisms. Users should update to macOS Tahoe 26.3 or later to remediate this vulnerability. The security update is available through Apple's standard software update channels and is documented in the Apple Support Article.

Workarounds

• Restrict application installations to trusted sources only (Mac App Store or identified developers)
• Enable macOS Gatekeeper to prevent execution of unsigned applications
• Apply principle of least privilege for user accounts to limit potential data exposure
• Consider temporary isolation of systems containing highly sensitive data until patches can be applied

# Verify macOS version to ensure patched version is installed
sw_vers -productVersion
# Expected output should be 26.3 or higher

# Enable Gatekeeper to restrict app installations
sudo spctl --master-enable

# Check Gatekeeper status
spctl --status